8th Autumn School on X-ray Scattering from …kfkl.cz/Smolenice/images/programSmolenice_2011.pdfWe describe x-ray diffraction from thin ﬁlms consisting of monolayers with different

$Page 1: 8th Autumn School on X-ray Scattering from …kfkl.cz/Smolenice/images/programSmolenice_2011.pdfWe describe x-ray diffraction from thin ﬁlms consisting of monolayers with different$

8th Autumn School on X-ray Scattering from

Surfaces and Thin Layers

4.-7. October 2011, Smolenice Castle, Slovakia

PROGRAM & ABSTRACTS

Final Program Smolenice 2011, October 4 - 7 2011

Tutorials Short contributions Posters

Tuesday 4.10. 2011 08:00 - 13:00

Arrival

13:00 Lunch

14:00 A01 Peter Zaumseil High Resolution X-Ray diffractometry (HRXRD)

15:30 Break

16:00 A02 O. Caha Numerical simulation of spontaneous lateral ordering in InGaP layers on GaAs(001)

16:30 A03 N. Hrauda X-ray diffraction and FEM modeling on SiGe islands for strain-enhanced applications

17:00 A04 V. Kopp Statistical model of layer disorder: analytical calculation of x-ray diffraction

17:30 A05 G. Kozlowski Structure characterization on selective Ge nanostructures on freestanding Si(001) patterns

18:00 A06 J. Matějová XRD-based determination of strain field in Si nanostructures for Ge-Si(001) nanoheteroepitaxy

18:30 A07 M. Kryśko Deformation of crystal unit cells of InGaN layers on miscut c-plane GaN-sapphire substrate templates

19:00 - 22:00 Get-together party

Wednesday 5.10.2011

8:00 Breakfast

9:00 A08 Ullrich Pietsch Investigation of surface nanostructures by x-ray diffraction and x-ray imaging

10:30 Break 11:00 A09 L. Berger Thermal induced changes in microstructure of Nb2O5 deposited onto a Pt bottom electrode

11:30 A10 J. Růžička X-ray Laue diffraction study of Oxygen precipitates in Czochralski Silicon

12:00 A11 A. Davydok Crystal structure of InAs grown onto Si(111) substrate

12:30 A12 B. Khanbabaee Structure and strain analysis of iron implanted Si surface by using depth-dependence x-ray diffraction methods

13:00 Lunch

14:00 A13 Václav Holý Grazing-incidence x-ray small-angle scattering from self-assembled nanoparticles

15:30 Break

16:00 A14 G. Bussone Characterization of HPHT diamond crystals for x-ray optical elements: Investigation of surface damage by x-ray reflectivity and in-plane grazing-incidence diffraction

16:30 A15 A. Davtyan X-ray reflectivity at samples at bended substrate

17:00 A16 I. Kiesel Temperature-induced denaturation of protein layers at solid-liquid interfaces - an x-ray reflectivity study

17:30 A17 D. Ksenzov Soft x-ray reflectivity of multilayers based on B4C near the boron K edge

18:00 A18 X. Marti Skin layer of BiFeO3 single crystals

18:30 A19 J. Wernecke Dimensional characterization of nanostructured surfaces with grazing-incidence small-angle x-ray scattering (GISAXS)

19:00 Dinner

20:00 - 22:00 Poster session

Final Program Smolenice 2011, October 4 - 7 2011

Tutorials Short contributions Posters

List

of

Pos

ters

A20 F. Anger Structure and morphology of fluorinated rubrene thin films

A21 A. Aufderheide Structural and optical properties of molecular mixtures of pentacene and diindenoperylene

A22 M. Barchuk Defect determination in epitaxial A-Plane gan layers

A23 Muhamath Basha Surface characterization of nanocomposite coatings on aluminium

A24 T. Djuric Polymorphism of epitaxially aligned tetraphenyl-porphyrin thin films

A25 K. Istomin New beamline BL-10 at DELTA synchrotron in Dortmund

A26 S. Lazarev Composition and strain investigation of the phase-separated InGaN quantum dots revealed from the AXRD reciprocal space maps

A27 A. Moser PyGid: A software for the analysis of grazing-incidence x-ray diffraction data

A28 M. Schmidbauer Ordering phenomena in In0.48Ga0.52P epitaxial layers grown on GaAs(001)

A29 P. Schroth Investigation of self-organized quantum dots using a protable synchrotron UHV MBE system

A30 N. Pashniak Measurements with the pn-CCD: A micro X-ray source application for SAXS.

A31 S. Gorfman High-resolution X-ray difraction studie sof ferrolectric perovskites

A32 M. Ruge Time-resolved in-situ GISAXS studies of the mesoscopic roughness during homeopitaxial electrodeposition on AU(001)

A33 R. Grifone Time-resolved X-ray diffraction study of LiNbO3 under pulsed external electric field.

A34 J. Grenzer FIB induced structural modifications in thin magnetic films.

Thursday 6.10.2011

8:00 Breakfast

9:00 A35 Joerg Grenzer In-situ X-ray Scattering: A Tool for Investigation of Nanostructure Formation

10:30 Break 11:00 A36 U. Ratayski In-situ high-temperature investigations of the interface reactions in nanoscaled Cr/Ta-C

multilayers using X-ray scattering

11:30 A37 A. Zimina In-situ x-ray scattering investigation with high-resolution at the NANO-beamline at ANKA during the growth

12:00 A38 K. Broch Real-time observation of structural and optical changes during film growth of equimolar mixtures of organic semiconductors

12:30 A39 Ch. Weber In Situ Growth Studies of n-Alkanes on Silica with Real-Time X-Ray Methods

13:00 Lunch

14:00 A40 Dirk Lützenkirchen-Hecht

Fundamentals and applications of grazing-incidence x-ray absorption spectroscopy

15:30 Break 16:00 A41 L. Grodd In-situ measurements of solidification of poly(3-hexylthiophene) solution during the

application of an external electric field

16:30 A42 O. Skibitzki GaP collector development of SiGe HBT performance increase: A heterostructure growth study

17:00 A43 L. Tarnawska X-ray diffraction study of GaN/Sc2O3/Y2O3/Si(111) heterostructures

17:30 A44 O. D. Roshchupkina Structural modification induced by FIB implantation in magnetic thin films

18:00 A45 M. Zoellner Studying the structure-stoichiometry relationship of mixed Ce(2-x)PrxO(3+d) (x=0-2) oxide catalysts on Si(111) by XRD

18:30 A46 A. Neuhold Characterization of Organic/Inorganic Interfaces by X-ray Reflectivity and Transmission Electron Microscopy

19:00 - 22:00 Dinner+Barbecue

Friday 7.10.2011

08.00 Breakfast

09.00 - …. Departure


Abstracts

A01HIGH RESOLUTION X-RAY DIFFRACTOMETRY (HRXRD)Peter Zaumseil11Im Technologiepark 25, 15230 Frankfurt (Oder), GermanyThe intention of this tutorial is to give an overview about the theoretical background and the main aspects of applicationof high resolution X-ray diffraction using modern laboratory-based diffractometers.Based on the reflection curves of ’perfect’ crystals described by the dynamical theory of X-ray diffraction, the main config-urations of double and multiple crystal arrangements are discussed. This includes the influence of wavelength contribution,symmetrical and asymmetrical reflections, multi-reflecting channel-cut crystals, mirrors, etc. Different examples will demon-strate that there does not exist the one and ultimate best diffractometer configuration. It is rather necessary to find the bestchoice depending on the existing problem of investigation.Email of the presenting author: [email protected]

A02NUMERICAL SIMULATION OF SPONTANEOUS LATERAL OREDRING IN INGAP LAYERS ON GAAS (001)Ondrej Caha1, Martin Schmidbauer2, Asli Ugur3, Fariba Hatami3, Ted W. Masselink31Masaryk University, Brno, Czech Republic2Leibniz-Institute for crystal growth, Berlin, Germany3Humboldt University, Berlin, GermanyLateral compositional modulation in epitaxial (In,Ga)P layers grown on GaAs (001) substrate has been observed along [-110] direction. We present results of the numerical simulations based on the theoretical description of the spontaneousdecomposition of the semiconductor alloy epitaxial layers due to the strain field. The results of the simulations are comparedto the x-ray diffuse measurements, which were provided in order to determine the modulation periodicity, amplitude andchemical composition in the layer.Email of the presenting author: [email protected]

A03X-RAY DIFFRACTION AND FEM MODELING ON SIGE ISLANDS FOR STRAIN-ENHANCED APPLICATIONSNina Hrauda1, Jianjun Zhang2, Julian Stangl1, Eugen Wintersberger3, Tanja Etzelstorfer1, Mario Keplinger1, DominikKriegner1, Vaclav Holy4, Vladimir Jovanovic5, Lis K. Nanver5, Detlev Grutzmacher6, Gunther Bauer11Institute for Semiconductor Physics, JKU Linz, Altenbergerstr. 69, 4040 Linz, Austria2IWF Dresden, Helmholtzstr. 20, 01069 Dresden, Germany3HASYLAB at DESY, Notkestr. 85, 22607 Hamburg, Germany4Faculty of Mathematics and Physics, Charles University Prague, Ke Karlovu 5, 12116 Praha, Czech Republic5DIMES, TU Delft, Feldmannweg 17, 2628 CT, The Netherlands6Halbleiter-Nanoelektronik (IBN-1) Forschungszentrum Julich GmbH, 52425 Julich, GermanyThe Si-Ge material system is not only an interesting topic for basic research but of high importance for advanced nanoscaledevices as well. To speed up Si-based transistors both tensile (for n-type) or compressive strain (for p-type) can be appliedto the Si channel of MOSFETs, depending on the set up. Several approaches exist to induce strain, like the application ofstressed nitride layers or the use of planar SiGe stressor structures. Our research focuses on the use of epitaxially grownSiGe islands, 3D structures that arise due to the lattice mismatch between Si and Ge. We present studies based on X-raydiffraction and finite element method modeling including both dome- and barn-shaped SiGe islands grown on prepatternedSi (001) substrates. The overgrowth of SiGe islands with Si results in tensile strain in the Si layer above the buried island.The amount of strain depends on several factors such as the composition of the buried island, its shape, or the thickness ofthe capping layer. Growing SiGe islands in a closely-spaced configuration results in compressive strain in the sections of theSi cap layer situated between those islands. We also show an example, where SiGe islands have successfully been integratedinto a transistor based on strained Si, and demonstrate that X-ray diffraction in the sub-micron range represents an excellenttool to investigate the internal structure of this devices in a nondestructive way. A focused synchrotron X-ray beam with adiameter of 400 nm was used to perform a diffraction experiment on a single SiGe island which serves as stressor for theSi-channel in a functioning MOSFET.Email of the presenting author: [email protected]

Smolenice 2011 Abstracts

A04STATISTICAL MODEL OF LAYER DISORDER: ANALYTICAL CALCULATION OF KINEMATICAL X-RAYDIFFRACTIONV. S. Kopp1, V. M. Kaganer1, J. Schwarzkopf2, F. Waidick2, M. Schmidbauer21Paul Drude Institute for Solid State Electronics, Berlin, Germany2Leibniz Institute for Crystal Growth, Berlin, GermanyWe describe x-ray diffraction from thin films consisting of monolayers with different thickness, structure, and chemicalcontent. The layer disorder is described by probabilities for different sequences of scattering elements. We consider thelayers of different thicknesses and structures that form a stationary Markov chain of rank 1. Closed analytical expressions forthe diffracted x-ray intensity are found. The analogy to the prominent Lent and Cohen model of surface steps is used. Theproposed model has been successfully applied to the diffraction data from epitaxial sodium-bismuth-titanate films possessingsuch one-dimensional disorder. The disorder is caused by random number of perovskite units separated by bismuth oxideinterlayers. The results of analytical calculations are in good agreement with the experimental data.Email of the presenting author: [email protected]

A05STRUCTURE CHARACTERIZATION ON SELECTIVE GE NANOSTRUCTURES ON FREE STANDING SI(001)PATTERNSG. Kozlowski1, P. Zaumseil1, M. A. Schubert1, Y. Yamamoto1, J. Bauer1, J. Matejova1,2, B. Tillack1,3, T. Schroeder11IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany2Charles University in Prague, Ke Karlovu 5, 121 16 Prague 2, Czech Republic3Technische Universitt Berlin, HFT4, Einsteinufer 25, 10587, Berlin, GermanyGe is attractive to build up future photonic devices due to its superior optoelectronic properties with respect to Si and itscompatibility with Si CMOS processing in contrast to III-V materials. The major stumble block for the integration of highquality Ge on Si is however given by the 4.2% lattice mismatch which causes misfit and threading dislocation (TD) formation.A promising method to reduce the density of TD is to grow Ge selectively in a limited area. We focus on the characterizationstudies of Ge selectively grown on free-standing mesa structured Si(001) with sidewall and trench covered by SiO2. Next toa decreased number of sites for dislocation nucleation, we expect dislocations to glide to the edge of mesas.Synchrotron-based grazing incidence X-ray diffraction is applied to study the epitaxial relationship, defect and strain char-acteristics with high resolution and sensitivity in a non-destructive way. In addition, special focus is devoted to transmissionelectron microscopy (TEM) to determine the quality of the Ge epilayer.We found, that although the nanopatterned substrate is stressed by SiO2, the Si structure quality is not affected. The epi-Ge crystal grows in a relaxed form. It is realized by relieving nearly the whole strain energy by the nucleation of a misfitdislocation network at the Ge/Si interface. In some of Ge clusters two different crystal orientations separated by a twinboundary were found. In consequence, Ge nanostructures with asymmetric shape were formed.Email of the presenting author: [email protected]

A06XRD-BASED DETERMINATION OF STRAIN FIELD IN SI NANOSTRUCTURES FOR GE/SI(001) NANOHETEROEPI-TAXYJana Matejova1, Peter Zaumseil1, Vaclav Holy2, Grzegorz Kozlowski1, Thomas Schroeder11IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany2Charles University in Prague, Ke Karlovu 5, 121 16 Prague 2, Czech RepublicIntegration of Ge on Si substrate is of increasing interest nowadays because of its possible application in photonics or CMOStechnologies. newline Classical planar heteroepitaxy results in a nucleation of dislocations in the Ge layer, since the latticemisfit between Ge and Si is relatively large. To reduce the number of defects in the Ge layer, epitaxial methods are un-der investigation that are able to decrease the elastic energy accumulated in the materials. newline Nanoheteroepitaxy is anovel approach, which provides a strain-relieving mechanism based on redistributing lattice-misfit energy between Ge filmand substrate by means of preparing free-standing nano-pillars on patterned Si wafers. Si nano-pillars are manufacturedlithographically, whereas Ge is deposited on their top by selective CVD. To avoid attaching Ge on the Si pillars side wallsand trench regions, creation of a growth mask is necessary. newline X-ray diffraction is a suitable method to yield bulkcharacteristics of nanostructured samples. In the presented study we concentrate on the investigation of the strain field in Sinano-pillars on Si substrate covered by SiO2 growth mask by analyzing high-resolution diffraction scans. newline We sug-gested an iterative procedure based on an evolutionary algorithm to find such a strain field in nanostructures that minimizesthe discrepancy between simulated and measured diffraction curves. Calculation of diffraction curves from the strain fielduses kinematical x-ray scattering theory with absorption corrections.Email of the presenting author: [email protected]


A07DEFORMATION OF CRYSTAL UNIT CELLS OF InGaN LAYERS ON MISCUT C-PLANE GaN-SAPPHIRE SUB-STRATE TEMPLATESMarcin Krysko1, Jaroslaw Domagala2, Michal Leszczynski11Institute of High Pressure Physics of the Polish Academy of Sciences, UNIPRESS2Institute of Physics of the Polish Academy of SciencesInGaN thin layers grown on miscut c-plane GaN-sapphire substrate templates were investigated with high resolution x-ray diffraction. The angle of the substrate templates miscut was up to 0.6o. The layers were fully strained to the substrate.Reciprocal space maps of six reflexes of the {1 1 2 4} set revealed, that unit cells of the InGaN layers are deformed: the [0 00 1] axis is tilted and is not perpendicular to the (0 0 0 1) plane. Angle of the tilt is 0.07o in the case of In0.18Ga0.82N layergrown on a substrate template with 0.6o miscut.We present a model describing possible mechanism leading to the deformation of unit cells. The values of the tilt of [0 0 0 1]axis derived from the model are lower than the measured ones, thus our model does not fully describe the phenomenon of theunit cells deformation.Email of the presenting author: [email protected]

A08INVESTIGATION OF SURFACE NANOSTRUCTURES BY X-RAY DIFFRACTION AND X-RAY IMAGINGUllrich Pietsch11University of Siegen, Walter-Flex-str. 3, Siegen, GermanyNanostructures such as nanowires and nanodots play an important role in present semiconductor technology. There is alarge interest to combine the crystallographic structure of the nanoobject with change in physical properties. Here spatiallyresolved x-ray diffraction and imaging techniques can play an important role. Using an x-ray beam with diameter of fewnanometers the incident beam is highly coherent which has consequences for the interpretation of diffraction data.We will show recent methodical achievements in focussing the synchrotron beam down to several 10 nm. Such nanobeamscan be used to determine the shape of the nanoobject by coherent diffraction imaging and subsequent phase retrieval usingthe recorded 3D intensity distribution. Meanwhile this technique is well applied on semiconductor- and bio-objects includingachievements for local strain analysis. Alternative one can use the nanobeam to record reciprocal space maps of individualnanoobjects and to compare the structural properties of various objects grown on the same wafer. This method is well suitedto study the individual structure of nanoobjects as function of growth condition and to understand the strain accommodationof highly strained nanoobject onto the underlying substrate during MBE or MOVPE growth.The tutorial will introduce in the basics of thin film and nanostructures analysis by x-ray diffraction techniques and willdemonstrate the achievements by presenting various examples of experimental results.Email of the presenting author: [email protected]

A09THERMAL INDUCED CHANGES IN MICROSTRUCTURE OF Nb2O5 DEPOSITED ONTO A Pt BOTTOM ELEC-TRODELysann Berger 1, Hannes Mahne2, David Rafaja 1, Thomas Mikolajick 2,3

1Institute of Materials Science, TU Bergakademie Freiberg, Gustav Zeuner Str. 5, D-09599 Freiberg, Germany2Namlab GmbH, Nothnitzer Str. 64, D-01187 Dresden, Germany3Institute of Semiconductor and Microsystems Technology, TU Dresden, Nothnitzer Str. 64, D-01187 Dresden, GermanyA resistance random access memory (ReRAM) is a new non-volatile two terminal memory. Resistive memory devices maybe capable of overcoming the scaling limits conventional semiconductor memory like DRAM or Flash. The basic idea of theRRAM is that a normally insulating dielectric film, in this work Nb2O5, between two electrodes can be made conductive byapplying a high electric field. As a reversible process, it enables a write and erase operation for single bits and thus storesinformation.The main goal of this work was to describe the microstructure of the Nb2O5/Pt/TiO2/SiO2/Si sandwiches after the deposi-tion and subsequent heat treatment and the thermal induced interfacial reactions at the Nb2O5/Pt interface. For this reason,Nb2O5 thin films were deposited onto thermally oxidized Si (100) substrates that were covered first by a Ti and a Pt film. Thedeposition of Ti and Pt was performed in a DC sputtering at room temperature. After the deposition of each film (Ti and Pt),the samples were oxidized at 700oC in oxygen atmosphere. The Nb2O5 thin films were deposited by using the reactive DCsputtering in oxygen atmosphere and then annealed in a rapid thermal process (RTP) in argon atmosphere at the temperaturesbetween 500oC and 700oC.The samples of Nb2O5/Pt/TiO2/SiO2/Si were investigated by using X-ray reflectivity (XRR), small angle X-ray scattering(SAXS) and glancing angle X-ray diffraction (GAXRD). XRR revealed the individual layer thicknesses, electron densitiesand interfacial roughness. Additional information on the correlation of the roughness was obtained from SAXS. With increas-ing temperature, the thin films showed increasing electron density and a reduction in the thickness of both, Pt and Nb2O5.For the Nb2O5 film, a continuous crystallization and the formation of the orthorhombic structure was observed by GAXRDabove 600oC. Up to 650oC, the surface roughness of the samples was low (∼ 1nm) and almost constant, it increased slightlyafter the thermal treatment at higher temperatures.Email of the presenting author: [email protected]


A10X-RAY LAUE DIFFRACTION STUDY OF OXYGEN PRECIPITATES IN CZOCHRALSKI SILICONJirı Ruzicka1, Mojmır Meduna1, Ondrej Caha11Masaryk University, Brno, Czech RepublicSilicon crystals pulled by Czochralski method contain large amounts of interstitial oxygen. During thermal treatment theoxygen atoms are driven by diffusion and gather forming oxygen precipitates. These precipitates work as traps for metalions and dislocations and therefore they help to protect the electronic devices created in the surface layer of the crystal. Theprecipitates can be studied using x-ray diffraction, either in Bragg or Laue geometry. We measured the transmission andreflection curves of thermally treated crystals in Laue geometry. Using statistical dynamical theory of diffraction it is possibleto calculate the curves for given model of the defects whose cores are formed by the precipitates. We assumed the defects tobe spherical in shape, homogeneously distributed, nondiffracting and not deforming the surrounding lattice. The parametersof the calculation used were the radius of the defects and the volume of the defects relative to the volume of the crystal. Ab-solute concentration of the defects can be calculated using these values. We studied the dependence of the defect parameterson the high temperature pre-anneal, the nucleation temperature and the duration of the precipitation anneal.Email of the presenting author: [email protected]

A11CRYSTAL STRUCTURE OF INAS GROWN ONTO SI(111) SUBSTRATEA. Davydok 1, E. Dimakis2, A. Biermanns 1, S. Breuer2, L. Geelhaar 2, U.Pietsch 1

1Festkorperphysik, Universitat Siegen, Walter-Flex-Str. 3,57072, Siegen, Germany2Paul-Drude-Institut fur Festkorperelektronik, Hausvogteiplatz 5-7,10117 Berlin, GermanyNanowires (NW) grown by molecular beam epitaxy (MBE) in vapor-liquid-solid (VLS) mode are of particular interest dueto the ability to synthesize single-crystalline 1D epitaxial structures and heterostructures in the nanometer range. Nowa-days nanowires have already found application as single-electron transistors (SET), resonant tunnelling diodes, light emittingdiodes (LED), photo detectors. However, several structural aspects of the self-assisted VLS growth process are not wellunderstood so far. It was found that by VLS growth nearly any AIIIBV semiconductor material can be grown as NWs ontoanother AIIIBV or group IV [111] substrates independent from lattice mismatch, such as InAs on Si(111) with lattice mis-match of 11%. We investigated growth samples series where the NW growth was stopped after 10, 43, 86 and 7200seconds.Preor X-ray experiment samples were inspected with scanning electron microscopy. We have performed X-ray reciprocalspace mapping (RSM) in vicinity of selected Bragg reflections to analyze structural changes during the growth process. Inparticular we observed the evaluation of InAs (111) signal with growth time. At sample with two hours growth time one findsa superposition of two hexagonal cross-sections. The cross-sections are rotated by 30 with respect to each other correspond-ing to transition from {1 -1 0} side-facets towards {1 1 -2} facets. Considering the time evolution of this feature we attributethe {1 -1 0} appearing first to wurtzite (larger c- lattice parameter) and the second one with {1 1 -2} to zincblende appearingat later stage of NW growth.Email of the presenting author: [email protected]

A12STRUCTURE AND STRAIN ANALYSIS OF IRON ION IMPLANTED SI SURFACE BY USING DEPTH DEPEN-DENCE X-RAY DIFFRACTOIN METHODSB. Khanbabaee1, S. Fasco.2, J. Grenzer2, U. Pietsch11Solid State Physics, Siegen University, 57068 Siegen, Germany2Helmholtz-zentrum Dresden-Rossendorf,01314 Dresden, GermanyIon beam sputtering or ion beam erosion of semiconductor surfaces can be used to modify the surface topography on differentlength scales. Under oblique ion bombardment and using ion energies >20keV, surface ripple formation is observed accom-panied by a buried ripple structure at the amorphous-crystalline interface with the same lateral spacing as found at the surface[1-2]. In addition structural defects are created inducing lattice strain. X-ray rocking curve analysis is the appropriate tool fornon-destructive characterization of lattice strain. Considering [001] surfaces of silicon symmetrical reflection such as (004)cannot be used for strain analysis because of the large penetration depth of x-ray beam into the sample. For this reason weemployed the extremely asymmetric diffraction (EAD) scheme for sample to change the effective penetration depth. Usingfixed x-ray energy the incidence angle with respect to the sample surface is changed by rotation of the sample around thenormal of the diffracting lattice planes resulting in different absorption lengths, tabs measured normal to the surface [3]. Incase of a strained surface layer a decrease of tabs results in an increase the intensity ratio between the strained and unstrainedpart of the specimen.In this work we present results of the investigation Si [001] samples implanted by iron atom at 20 keV,50 keV and 100keV under normal and oblique incidence. Probed by AFM the surfaces are found to be smooth for samplesunder normal incidence but very rough under oblique incidence. X-ray reflectivity (XRR) gives evidence of layer formationdue to iron incorporation. We observe thickness oscillations corresponding to a layer of 22nm, 47 nm and 76 nm for 20,50 and 100keV implantation, respectively. Using EAD at incidence angle of one degree we could indentify iron-silicide asformed material in the surface layers. Strain profile of incorporated iron ions have been investigated by using EAD in Homelab using at wavelength of 0.154 nm. Here the (113) and (133) lattice planes were probed being inclined by φ=25.23 degreeand φ=46.51 degree with respect to (001) surface. Due to enhance surface sensitivity a near surface relative lattice expansionof about +5*10−4 was detected. This expanded layer was not found for samples prepared under oblique implantation whichcan be explained by strain release via the enlarged surface.Email of the presenting author: [email protected]


A13GRAZING-INCIDENCE X-RAY SMALL-ANGLE SCATTERING FROM SELF-ASSEMBLED NANOPARTICLESVaclav Holy11Charles University in Prague, Czech Republic.emiconductor, metallic or dielectric nanoparticles are intensively studied nowadays for their unique physical properties. Thenanoparticles are usually prepared by a self-organization process, in which the positions and sizes depend on the parametersof the growth. The self-organization is a stochastic process so that the parameters of the particles exhibit random variationsfrom their mean values.Small-angle x-ray scattering is widely used for the investigation of random ensembles of particles. The tutorial will presentthe basics of x-ray scattering theory necessary for the description of small angle scattering and grazing-incidence small anglescattering (GISAXS). Attention will be paid to the models of particle arrangement following from the self-organization pro-cess and several experimental examples will be presented.Email of the presenting author: [email protected]

A14CHARACTERIZATION OF HPHT DIAMOND CRYSTALS FOR X-RAY OPTICAL ELEMENTS: INVESTIGA-TION OF SURFACE DAMAGE BY X-RAY REFLECTIVITY AND IN-PLANE GRAZING INCIDENCE DIFFRAC-TIONGenziana Bussone1, Tamzin A. Lafford2, Fabio Masiello2, Alain Gibaud3, Gerardina Carbone2, Tobias U. Schulli2, SimonH. Connell4, Amparo Vivo Rommeveaux2, Matthew Wormington5, Jurgen Hartwig21University of Siegen, Walter-Flex-Str. 3 , Siegen, 57068, Germany2European Synchrotron Radiation Facility, 6, rue Jules Horowitz, BP 220, 38043 Grenoble Cedex 9, France3Laboratoire PEC, Universit du Maine le Mans, Avenue Olivier Messiaen, 72 085 Le Mans, France4University of Johannesburg, cnr Kingsway Ave and University Rd, Auckland Park, 2006, Johannesburg, South Africa5Jordan Valley Semiconductors Inc., 8601 Cross Park Drive, Suite 200, Austin, TX 78754-4578, USAHigh quality single-crystal synthetic diamond is the most suitable material for selected X-ray optical applications in thelatest generation X-ray light sources. Excellent heat handling properties, as well as low absorption, coupled with high per-fection in the crystal bulk and very good surface quality, compared to silicon, which is currently widely used, are crucial forsuch applications. Since the early 1990s synthetic diamonds have been tested and used for such elements at third generationsynchrotron radiation sources. This was almost exclusively nitrogen-rich material of rather low bulk quality and limited di-mensions. In recent years, some progress has been made in the fields of surface treatments and growth techniques (diamondmaterial with very low nitrogen concentration (< 0.1 ppm) is produced). However a considerable effort is still needed inimproving the surface (polishing) quality. Conventional scaife polishing is largely ineffective on the diamond (111) surface.To overcome this disadvantage, one possibility is to use the Hot Metal polishing technique. An investigation of surface andsub-surface damage of Hot Metal polished and cleaved surfaces, has been carried out using depth-sensitive non-destructive X-ray techniques, performed at the European Synchrotron Radiation Facility (ESRF) in Grenoble. The near surface crystallinequality was studied as a function of depth using in-plane grazing incidence X-ray diffraction. Additionally, X-ray reflectivitywas used to investigate the density, thickness and roughness of near-surface layers. The measurements enable us to estimatethe thickness of the affected sub-surface layer.Email of the presenting author: [email protected]

A15X-RAY REFLECTIVITY AT SAMPLES WITH BENDED SUBSTRATEArman Davtyan1, Dmitriy Ksenzov1, Christoph Schlemper1, Ullrich Pietsch11Solid State Physics Group, University of Siegen, 57068 Siegen, GermanyX-ray free electron lasers (FEL) have been installed or are currently under construction at several places in the world. Theyopen fascinating possibilities for dynamic experiments with femtosecond time resolution. In present we introduce an ex-perimental setup which helps us to record the whole rocking of the first Bragg peak using only few shots of X-ray beam atBESSY 2. In order to get the whole rocking curve of Ru/B4C multilayer was first banded with banded radius 130 mm andinstalled on motor which allows to move sample on z direction. Reflectivity of the Ru/B4C ML as a function on wave vectorq for energy ranges in between 175-200eV was taken. It was shown that after Carbon K edge reflectivity is very low becauseof abortion. Composition of scattering curves was taken at different z-positions for 182eV and 192eV, and they are in goodagreement with theoretical calculations. Using cylindrically bent structures we can study time-dependent processes duringinteraction of ultra-short X-ray pulses with the electronic structure of investigated object. Because we can reconstruct therocking curve pulse by pulse we are able to see small changes in Bragg peak position and intensity. The process of electron-photon coupling may proceed via various intermediate states where the electrons become condensed to electron-hole plasma.All these different state may cause alteration of the diffraction curve.Email of the presenting author: [email protected]


A16TEMPERATURE INDUCED DENATURATION OF PROTEIN LAYERS AT SOLID-LIQUID INTERFACES ANX-RAY REFLECTIVITY STUDYIrena Kiesel1, Michael Paulus1, Julia Nase1, Sebastian Tiemeyer1, Christian Sternemann1, Metin Tolan11Fakulty Physik/DELTA, TU Dortmund, Maria-Goeppert-Mayer-Str. 2, 44227 Dortmund, GermanyProtein adsorption at solid/liquid interfaces is crucial for implants in human bodies. As denatured proteins lose their function-ality, they influence the acceptance of implants. In our experiment we have investigated the denaturation process induced byincreasing temperature. Until now, most denaturation experiments were performed in protein solutions. However, a solution,which represents a protein reservoir, affords further protein adsorption during the denaturation process.newline Therefore,we have prepared hydrophilised silicon wafers with a natural oxide layer by placing them in a protein buffer solution untila protein layer was accrued. The used model proteins are lysozyme, albumin and RNase. In-situ x-ray reflectivity mea-surements were performed on these protein coated silcon wafers in pure buffer solution and in protein buffer solution. Thex-ray reflectivities at different temperatures up to 90oC were recorded using the 27 keV x-ray reflectivity setup of BL9 at thesynchrotron source DELTA. The denaturation process could be investigated by analyzing the (layer) electron density profileand with this, information on structural changes of the protein film induced by temperature was obtained.newline Financialsupport by BMBF project 05K10 PEC.Email of the presenting author: [email protected]

A17SOFT X-RAY REFLECTIVITY OF MULTILAYERS BASED ON B4C NEAR THE BORON K EDGED. Ksenzov1, C. Schlemper1, A. Davtyan1, U. Pietsch11University of Siegen, Walter-Flex Strasse 3, 57068 Siegen, GermanyEnergy dependence of the optical constants of boron carbide in the short period multilayers (MLs) are evaluated from com-plete reflectivity scans across the Boron K edge using the resonant soft X-ray reflectivity technique (RSoXR). A combinationof data obtained by hard and soft x-ray measurements provides detailed information about the properties of the Me/B4CMLs with a few tens of periods. The measurements close to the resonance edges probe the chemical state of the respectiveconstituent, accompanied with a high sensitivity of changes close to the sample surface.In the wide-angular geometry, the optical properties of B4C inside the ML were calculated from experimental data by RSoXRmethod. The obtained values of δ and β demonstrated the molecular nature of boron carbide and the dependence of metal-lic layers. The penetration depth of the MLs is strongly reduced beyond the Boron K edge and reaches only a few tens ofnanometers. In the case of the kinematic approximation, the δ and β values can be derived independently from each other.Unlike the Mo/B4C ML with narrow barrier layers, the Ru/B4C ML has wide interdiffusion layers and Ru-rich layers thatcontain a boride phase RuB2, which strongly modified the scattering properties near the boron Kα line. In the small-anglegeometry, the surface layers begin to play an important role, and it was found that the optical properties of these layers aredifferent from the properties of materials within the ML. Accordingly the optical properties of ultrathin ML structures with asmall number of periods will strongly depend on the properties of the surface layers.Email of the presenting author: [email protected]

A18SKIN LAYER OF BIFEO3 SINGLE CRYSTALSXavier Marti1, Julia Herrero-Albillos2, Pilar Ferrer Marti3, Vaclav Holy1, Marin Alexe4, Gustau Catalan51 Charles University in Prague, Czech Republic2Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH, Berlin, Germany3SpLine (BM25), ESRF, Grenoble, France.4Max Planck Institute of Microstructure Physics, Halle, Germany5Institut Catala de Recerca i Estudis Avan?s (ICREA), Catalunya, SpainBiFeO3 has become the cornerstone of magnetoelectric multiferroic research and, yet, its phase diagram is still an enigma,with several structural and/or functional anomalies reported as a function of temperature that may or may not signal the exis-tence of phase transitions. An unaddressed issue concerns the existence or otherwise of a surface layer (a ”skin”) in BiFeO3analogous to the known ones in SrTiO3, BaTiO3, or relaxor Pb(Mg0.33Nb0.66)O3. Here we will show by impedance analysisand grazing incidence x-ray diffraction that there is a surface layer (”skin”) functionally and structurally different from thebulk in BiFeO3 single crystals, with a surface-confined phase transition at T*=275 oC. We will discuss our results in the frameof previous reported experiments. Since BiFeO3 spintronic devices are based on interfacial coupling, the present results willbear on their performance.Email of the presenting author: [email protected]


A19DIMENSIONAL CHARACTERISATION OF NANOSTRUCTURED SURFACES WITH GRAZING INCIDENCESMALL ANGLE X-RAY SCATTERING (GISAXS)Jan Wernecke1, Michael Krumrey1, Levent Cibik1, Stefanie Marggraf1, Peter Mueller11Physikalisch-Technische Bundesanstalt Berlin, GermanySince manufactured structures in science and industry (such as next-generation EUV gratings, new photovoltaic devices,nanostructured catalysts) have reached nanometer-scale dimensions, there is an ever increasing demand for reliable methodsto determine structural parameters in the nanometer-scale range (nanometrology). The method we have chosen for measure-ments of statistically averaged dimensional properties of nanostructures on surfaces is Grazing Incidence Small Angle X-rayScattering (GISAXS). This is a versatile technique to probe statistic properties such as mean particle size, spacial distributionand roughness of nanostructured surfaces and nanoparticle assemblies on top of or buried in bulk material. The GISAXSexperiments were performed at the Four-Crystal Monochromator (FCM) beamline in the laboratory of PTB at the electronstorage ring BESSY II using the SAXS setup of the Helmholtz-Zentrum Berlin (HZB). In this presentation, a short overviewof instrumentation and capabilities of the laboratory to perform nanometrology with GISAXS will be given and experimentalresults and analysis methods of selected sample systems will be shown. Different gratings for EUV lithography have beeninvestigated in terms of grating period, groove density, coating layer thickness, and blaze angle. Furthermore, dimensionalproperties of gold nanoparticles on top of silicon substrate were determined. The obtained particle sizes were in good agree-ment with SAXS measurements of these particles in liquid suspension.Email of the presenting author: [email protected]

A20STRUCTURE AND MORPHOLOGY OF FLUORINATED RUBRENE THIN FILMSFalk Anger1, Evelyn Adamski1, Alexander Gerlach1, Jiri Novak1, Toshiyasu Suzuki2, Frank Schreiber11Institute for Applied Physics, Auf der Morgenstelle 10, 72076 Tuebingen, Germany2Institute for Molecular Science, Myodaiji, Okazaki 444-8787, JapanA promising way to modify the electronic levels of organic semiconductors is partial or complete fluorination of the molecularstructure of the materials. Rubrene (C42H28) has been shown to be a suitable semiconductor for applications. In this study,we present thin films of partly (C42H14F14) and completely (C42F28) fluorinated rubrene. For the first time we investigatedthin films of these materials grown on SiO2 using X-ray reflectivity, AFM, and we also performed complementary opticalspectroscopy. The materials grow to a large extent in an amorphous structure and exhibit a smooth surface. However, de-pending on the growth parameters the molecules can form ordered, dendritic structures that extend on a micrometer scale.Email of the presenting author: [email protected]

A21STRUCTURAL AND OPTICAL PROPERTIES OF MOLECULAR MIXTURES OF PENTACENE AND DIIN-DENOPERYLENEA. Aufderheide1, K. Broch1, C. Frank1, G. Ligorio1, J. Novak1, R. Nervo2, A. Gerlach1, F. Schreiber11Institut fur Angewandte Physik, Universitat Tubingen, Auf der Morgenstelle 10, 72076 Tubingen, Germany2ESRF, 6 Rue Jules Horowitz, BP 220, 38043 Grenoble Cedex 9, FranceOrganic semiconductors are promising materials for future optoelectronic applications such as organic photovoltaic cells(OPVCs) and organic light emitting diodes (OLEDs).In this context investigations of organic thin films of two compounds, one electron acceptor and one donor material are ofgreat importance. These heterostructures can be assembled in different architectures, e.g. planar heterojunctions or molecu-lar mixtures (bulk heterostructures). They are characterised by their optical and structural properties, which determine theirusability for devices [1].Here we present ex-situ x-ray reflectivity (XRR) and grazing incidence x-ray diffraction (GIXD) data in combination withoptical spectra of blended pentacene (PEN)-diindenoperylen (DIP) thin films with different mixing ratios. We observe strongchanges in the optical spectra dependent on the mixing ratio. The data from x-ray diffraction measurements give insightinto the ordering and mixing behaviour. By measuring GIXD we investigated possible phase separation as it was observedfor pentacene-perfluoropentacene mixtures [2]. The comparison of optical and x-ray data shows the influence of structuralchanges on the optical spectra.[1] A.Opitz et al., IEEE 16, 1707 (2010)[2]A.Hinderhofer et al., J.Chem.Phys. 134, 104702 (2011)Email of the presenting author: [email protected]


A22DEFECT DETERMINATION IN EPITAXIAL A-PLANE GAN LAYERSMykhailo Barchuk1, Vaclav Holy1, Dominik Kriegner2, Julian Strangl2, Stephan Schwaiger3, Ferdinand Scholz31Charles University in Prague, Czech Republic2Johannes Kepler University, Linz, Austria3Ulm University, GermanyTechnological applications of optoelectronic devices based on (0001), i.e., c-oriented GaN are complicated by the piezo-electric effect along the [0001] direction. This phenomenon gives rise to a band bending, known as the quantum confinedStark effect [1].Non-polar or semipolar GaN thin films overcome this problem. However, this type of material possesses a large numberof defects, especially stacking faults (SF) so that a reliable method for the determination of the defect densities is of largeimportance.We investigate non-polar a-plane oriented GaN epitaxial layers with the (11-20) surface orientation. In the layers of a-planeGaN, two types of basal plane stacking faults with the displacement vectors R = 1/62023 and 1/31100 are the most typicaldefects [2]. Another defect types (extrinsic basal stacking faults withR =1/2(0001), prismatic stacking faults withR=1/21011) can also occur but their formation energy is significantly higher so that one can neglect their influence [3].For the detection of SFs by x-ray diffraction, the visibility criterion can be applied. If g ·R 6= n (g is the diffraction vector, n isan integer), the diffuse x-ray scattering from the SFs has the form of [0001]-oriented streaks perpendicular to the fault planes;if g · R = n the defects are generally invisible by x-ray diffraction [4]. In the latter case, (for example in 3030 diffraction)a broadening of the diffraction maximum is observed caused by another defects such as dislocations, wafer curvature, andsurface roughness.We investigated a series of 4 samples grown by MOVPE technique [5] with various densities of stacking faults. The x-raydiffraction (XRD) measurements were performed using a custom built rotating anode setup. A double bent parabolic mul-tilayer mirror and a Ge(220) channel cut monochromator were used to produce a parallel beam of CuKα1 radiation. Thediffracted radiation was measured by a linear multichannel detector.The reciprocal space maps of diffracted intensity were measured in a non-coplanar Bragg geometry. In order to reach thediffractions 1010 and 2020 , in which the visibility criterion is fulfilled, and using the scattering plane containing the [0001]streak direction, this scattering plane had to be tilted by 30 deg with respect to the surface normal. For comparison, wemeasured also the reciprocal space maps in 3030 , where the visibility criterion is not fulfilled.All the measured diffraction maxima are broader than expected from the estimated instrumental broadening. However, sincewe are interested in the shape of the peaks far from the sharp central peak, the resolution function does not influence ouranalysis.Our model of simulation enables to calculate the profiles along the streaks in any diffraction. As input parameters we use thedensity of SFs, the coherence width of the primary beam and the shape factor of the coherence function in direct space. Usingthe Monte Carlo method we generate the positions of defects as a random Markov-like sequence. Then, we compute thedisplacement field caused by defects, and finally applying the kinematical approximation we obtain the intensity distributionalong the [0001] direction in reciprocal space.Comparison of the measured intensity distributions along the streaks with simulations supposing allows us to determine theprevailing displacement vector R of the SFs and their density.This work has been supported by the Grant Agency of Charles University in Prague (projects SVV 263307 and 22310)[1] F. Bernardini, V. Fiorentini, and D. Vanderbilt, Rhys. Rev. B 56, R10024 (1997).[2] D.N. Zakharov, Z. Liliental-Weber, B. Wagner, Z.J. Reitmeier, E.A. Preble, and R.F. Davis, Phys Rev. B 71, 235334(2005).[3] M.A. Moram, C.F. Johnston, J.L. Hollander, M.J. Kappers, and C.J. Hupmhreys, Physica B, 404, 2189-2191 (2009).[4] P. Hirsch, A. Howie, R. Nicholson, D.W. Pashley and M.J. Whelan, Electron Microscopy of Thin Crystals, Krieger Pub-lishing Company, Malabar, Frorida (1977).[5] S. Schwaiger, F. Lipski, T. Wunderer, and Ferdinand Scholz, Phys. Status Solidi C 7, No. 7-8, 2069-2072 (2010)Email of the presenting author: [email protected]

A23SURFACE CHARACTERIZATION OF NANOCOMPOSITE COATINGS ON ALUMINIUMMubarak Ali Muhamath Basha1, Raj Vairamuthu11Department of Chemistrz, Periyar University, Salem-636011, Tamil Nadu, IndiaThick ceramic nanocomposite coatings synthesized on aluminium for surface characterization under various conditions (elec-trolyte concentration, processing time, temperature and current density) and their thickness, growth rate, and hardness havebeen studied. The final coating thickness depends predominately on the processing time and the applied current density. Theconcentration of silicate in the electrolyte has significant effect on the resulting coating thickness, and surface morphology.The surface structure and composition were then characterized by means of scanning electron microscopy (SEM) with en-ergy dispersive spectroscopy (EDS) and atomic force microscopy (AFM). Changes in structural aspects and plane orientationswere monitored using x-ray diffraction method. Overall this paper highlights the important influence of the current densityon the microstructure, microhardness and structural aspects of the nanocomposite coating. The improved performance of thenanocomposite coated aluminium appears to be related to the formation of a more compact coating.Email of the presenting author: [email protected]


A24POLYMORPHISM OF EPITAXIALLY ALIGNED TETRAPHENYL-PORPHYRIN THIN FILMSTatjana Djuric1, Thomas Ules2, Sina Gusenleitner2, Navaphun Kayunkid3, Harald Plank4, Christian Teichert5, GregorHlawacek6, Martin Brinkmann3, Michael G. Ramsey2, Roland Resel11 Institute of Solid States Physics, Graz University of Technology, Austria2 Institute of Physics, Karl-Franzens University Graz, Austria3 Institut Charles Sadron, CNRS - Universite de Strasbourg, 23 rue du loess, 67034 Strasbourg, France4 Institute for Electron Microscopy, Graz University of Technology, Austria5 Institute of Physics, Montanuniversitaet Leoben, Austria6Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217,7500AE Enschede, The NetherlandsPorphyrin molecules, of interest as versatile materials for organic electronics, are highly prone to formation of significantlydifferent polymorphic phases. To elucidate the determinants for the specific polymorphic phase formed in thin films as wellas for the arrangement of the molecules on a given substrate two different anisotropic substrate surfaces have been selected:KCl(100) and the oxygen reconstructed Cu(110) surface. We observe that the crystal structure of the thin films depends on thesubstrate, whereas the relative molecular orientations in both cases are similar. X-ray and transmission electron diffraction of30 nm thick tetraphenyl-porphyrin (H2TPP) and platinum tetraphenyl-porphyrin (PtTPP) thin films deposited on KCl(100)surfaces reveal that both kind of molecules crystallize in a tetragonal polymorph with the (001) lattice planes, i.e. with theirmacrocycles, parallel to the substrate. Films deposited on oxygen reconstructed Cu(110)-(2x1)O surface exhibit in contrastthe triclinic polymorph even though molecules again align nearly parallel to the substrate surface as observed by LEED andX-ray diffraction. On both substrates we identify two driving forces for the epitaxial alignment of porphyrins: (i) moleculesaligning with their macrocycles (nearly) parallel to the substrate surface and (ii) the porphyrin molecules form a commen-surate unit cell with the respective substrate. The polymorphic phase meeting both requirements is the most favorable to beformed on a given substrate and due to this structural flexibility in both cases well-ordered, epitaxially aligned porphyrin thinfilms are achieved.Email of the presenting author: [email protected]

A25NEW BEAMLINE BL-10 AT DELTA SYNCHROTRON IN DORTMUNDKonstantin Istomin11University of Siegen, Solid State Physics GroupResearchers and industrials are more and more concerned that high performance materials such as stainless duplex steelsdo not have infinite fatigue life, and failures or cracks may occur even after billions of loading cycles applied. The correla-tion of the microstructure of materials with relevant damage mechanisms is necessary to explain and predict the material’sbehaviour during very high cycle fatigue (VHCF). One has to find conditions where initial fatigue damage is stopped bymeans of microstructural barriers. The way to solve the problem is the identification of mechanisms that lead to initiationof local dislocation movements, microcrack formation and fatigue crack propagation. X-Ray diffraction technique is a non-destructive tool to investigate the evolution of local dislocations and crack development as a function of stress cycles applied.It can be performed both on a conventional laboratory source as well as on the new beamline BL10 at Delta synchrotron inDortmund, Germany. The present set-up at the BL10 includes a 4-circle kappa diffractometer and a fast point detector. Thebeamline uses x-rays from a superconductive asymmetric wiggler with the critical energy of 8 keV. Photon energies between5 and 30 keV are achievable with the typical photon flux in order of 109 photons/s/mm2 at 13 keV. First results from themeasurements will be presented.Email of the presenting author: [email protected]

A26COMPOSITION AND STRAIN INVESTIGATION OF THE PHASE SEPARATED INGAN QUANTUM DOTS RE-VEALED FROM THE AXRD RECIPROCAL SPACE MAPSS. Lazarev1, M. Koehl1, B. Miljevic1, S. Bauer 1, T. Baumbach11Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany, GermanyGroup-III-Nitrides semiconductors present suitable applications in microelectronic and optoelectronic. InGaN quantum dots(QDs) are used for high emittance photonic devices with a tuneable output in the blue, green and ultraviolet spectral range. Anew method based on Metal-Organic Vapour Phase Epitaxy (MOVPE) has been introduced to form the QDs directly on thetop of the buffer layer. When depositing a thin nucleation layer on the top of buffer, with a layer thickness below the criticalthickness for island formation in Stranski-Krastanov mode, flat and broad island-like structures develop. Due to the inherentproblem associated with lattice mismatch between InN and GaN, heteroepitaxial growth is still not well understood. For thisexperiment there are series of samples with freestanding and caped QDs grown at different temperatures. Previous study onsame samples by grazing incidence diffraction (GID) and atomic force microscopy (AFM) have shown two type of InGaNislands with different composition. As GID is not a method which can clearly separate the composition from the strain effect,we performed asymmetrical XRD. Here we report on the reciprocal space mapping by AXRD reflection (10-15). From RSMone can estimate three different spots, among which one will correspond to GaN and the two others to InGaN with differentcontent in Indium. Therefore using the Vegards law combined with the relaxation condition we can simulate the positions ofInxGa(1-x)N in reciprocal space map.Email of the presenting author: [email protected]


A27PYGID: A SOFTWARE FOR THE ANALYSIS OF GRAZING INCIDENCE X-RAY DIFFRACTION DATA.A. Moser1, M. Neuschitzer1, A. Neuhold1, T. Djuric1, J. Novak2, I. Salzmann3, M. Oehzelt4, R. Resel11Institute of Solid State Physics, Graz University of Technology, Graz, Austria2Institut fur Angewandte Physik, Universitat Tubingen, Tubingen, Germany3Institut fur Physik, Humboldt-Universitat zu Berlin, Berlin, Germany4Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH, Berlin, GermanyIn organic thin film transistor research the crystallographic structure of thin organic films is of serious interest. However,in thin films often so called surface induced crystallographic phases are formed, which are not existent in powders or singlecrystals. Hence, their structure cannot be solved with the well established techniques. Therefore, we are interested in per-forming full crystal structure solutions via reciprocal space mapping under grazing incidence conditions, which is a perfecttechnique to collect data about these systems. newline The presented software PyGid was developed during our efforts ofsolving surface induced crystallographic phases. This software is tailored to the evaluation of reciprocal space maps recordedwith a one dimensional detector. At the moment, three different input formats are supported: data files written by the SPECsoftware, data files from the software online at the W1 beamline at Hasylab as well as Bruker .raw files. The most importantfeatures of PyGid are quick and easy visualization of the data, transformation to q-space, indexation of Bragg peaks as wellas intensity extraction of intensity cuts along the horizontal and vertical directions and also along Debye-Scherrer rings. Theintensity can be integrated along the direction perpendicular to the cut. newline To demonstrate the capabilities of PyGid re-sults on the structural characterization of surface induced crystallographic phase of Pentacenequinone (PQ) on silicon oxideand PQ as well as Perfluoropentacene on graphite will be shown. Additionally, results on the behavior of pentacene thin filmsupon thermal treatment up to 500 K will be presented.Email of the presenting author: [email protected]

A28ORDERING PHENOMENA IN IN0.48GA0.52P EPITAXIAL LAYERS GROWN ON GAAS (001)Martin Schmidbauer1, Asli Ugur2, Christoph Wollstein2, Fariba Hatami2, Ferhat Katmis2, W. Ted Masselink2, Ondrej Caha31Leibniz-Institute for Crystal Growth, Germany2Institute for Physics, Humboldt-University Berlin, Germany3Brno University, Czech RepublicA one dimensional periodic surface corrugation on In0.48Ga0.52P epitaxial layers grown lattice matched on GaAs(001) sub-strates has been found which can be used as a natural template for further growth of well aligned InP quantum dot chains. Thesurface undulations are aligned long the [-110] direction and they exhibit a height of a few nanometers with a correspondingperiod of typically 30..60 nm. Their appearance and structural properties strongly depend on the layer thickness and on theMBE growth conditions: the corrugation is well pronounced at high growth temperature (T = 743 K) whereas the surface isvery smooth at low growth temperature (T = 713 K). Two samples fabricated at identical MBE growth conditions but withdifferent layer thicknesses are compared in this study. X-ray diffuse scattering has been applied to evaluate the strain field andIndium composition in the near surface regime. The thin InGaP layer exhibits only weak and irregular surface undulationsand no Indium enrichment could be detected in the near surface regime. On the other hand the thickerInGaP layer shows awell pronounced and regular periodic surface corrugation with a substantial enrichment of Indium in the near surface regime.The results will be discussed in view of a possible lateral compositional modulation inside the InGaP layers.Email of the presenting author: [email protected]

A29INVESTIGATION OF SELF ORGANIZED QUANTUM DOTS USING A PORTABLE SYNCHROTRON UHV MBESYSTEMP. Schroth1, T. Slobodskyy1, M. Riotte1, D. Grigoriev2, D. Schaadt3, T. Baumbach11Karlsruhe Institute of Technology (KIT), Institute for Synchrotron Radiation (ISS) / ANKA, Hermann-von-Helmholtz-Platz1 ,76344 Eggenstein-Leopoldshafen, Germany2KIT, Laboratory for Applications of Synchrotron Radiation (LAS), Engesser Str. 15, 76131 Karlsruhe, Germany3KIT, DFG-Center for Functional Nanostructures, Wolfgang-Gaede-Str. 1a 76131 Karlsruhe, GermanyCurrently an immense effort is dedicated to grow Quantum Dots (QDs) at well defined positions with precise control oversize, shape and composition. Most commonly the nanoscale patterns are defined by self organization during the epitaxialprocess. When coupled into stacks, they form three dimensional structures useful for photonics and spintronics applications.During growth of III/V QD stacks the ordering of the QDs is achieved by transferring ordering information from a grownlayer to the next one by the strain pattern induced in the spacer layer. While growing the spacer layer, the underlying QDsare annealed simultaneously. Our previous investigations have shown that the shape and the strain profile of individual QDsare changing during annealing. Furthermore, post growth annealing reduces the strain which accumulates during QD forma-tion. In this contribution we will present the first in-situ experiment using a Portable Ultra High Vacuum (UHV) MolecularBeam Epitaxy system (PMBE). In-situ measurements are the key to access the process and mechanisms of self-ordering ofsemiconductor nanostructures (e.g. InAs/GaAs quantum dots) during growth or post-growth annealing. To perform this kindof experiments the PMBE-system was used to maintain UHV conditions and control the sample position and temperature.Grazing Incidence Diffraction (GID) and Grazing Incidence Small Angle X-Ray Scattering (GISAXS) were used to gaininformation about the strain field induced by the QDs and the QDs shape and distribution. The data was collected duringin-situ annealing at beamline ID03 at ESRF.Email of the presenting author: [email protected]


A30MEASUREMENTS WITH THE PN-CCD: A MICRO X-RAY SOURCE APPLICATION FOR SAXS.Nadiya Pashniak11University of Siegen, GermanyThe pn-CCD (charge coupled device) detector is both energy and position sensitive. It provides a very good opportunityfor experiments in q-space at fixed scattering geometry. Here we demonstrate application for scattering at soft matter. Inparticular cellulose and P3HT-polymers have been investigated in transmission - SAXS geometry. The energy and positionresolution ability of the detector allows to use white x-ray radiation and to record data without movement of the sample. Themeasurements of cellulose (extracted from a pine wood sample) have been performed at BESSY II using an energy rangebetween 8 and 20 keV. The lattice constants, unit cell type, and the crystallite size were evaluated form the obtained diffrac-tion pattern applying line profile analysis. Measurements at P3HT polymer films have been performed using a home x-raytube with beam size of 56 µm2 (I µS- X-ray source) in SAXS geometry. The photon flux of 108 ph/s at the Cu Ka line wassufficient to record data with good quantum statistic to characterize the semi-crystalline structure of the polymer.Email of the presenting author: [email protected]

A31HIGH-RESOLUTION X-RAY DIFFRACTION STUDIES OF FERROELECTRIC PEROVSKITESS. Gorfman1, P.A. Thomas21Department of Physics, University of Siegen, Walter-Flex str. 3, D57072, Siegen, Germany2Department of Physics, University of Warwick, Gibbert Hill Road, CV4 7AL, Coventry, UKMixed-ion perovskites are known for their useful physical properties, such as ferroelectricity, giant piezoelectric effect, high-temperature superconductivity, etc. Apart from the pure academic interest in the fascinating physics of perovskites, there isalso a strong demand for wider use of their high technological potential.The aim of the current work is to revise the currently existing phase diagrams of important ferroelectric materials andundertake detailed study of the symmetry as a function of composition and a temperature. We have developed a specialhigh-resolution X-ray diffraction technique [1-3], which involves the use of two different diffractometer: (1) Oxford Diffrac-tion Gemini R CCD for exploring large areas of reciprocal space and (2) Panalytical XPert Pro MRD for high resolutionstudies of selected areas of reciprocal space. In doing so we to get the most precise up to date information about the sym-metry of a single ferroelectric domain in the twinned crystals of ferroelectric. It is achieved by observation and analysis ofsplitting of peaks, arising from different ferroelectric domains.In this talk we will review the application of the new experimental technique for the investigation of symmetry of a fewtechnologically important ferroelectric perovskite materials [1-3].References:[1] Gorfman, S., Thomas, P.A. J Appl Cryst 43, 1409-1414, (2010)[2] Gorfman, S., Keeble, D.S., Glazer A.M., Long, X., Xie, Y., Ye, Z.-G., Collins, S., Thomas, P.A., Phys Rev B84, 020102R,(2011)[3] Datta, K., Gorfman, S., Thomas, P. A. Appl Phys Lett, 95 (25), (2009)Email of the presenting author: [email protected]

A32TIME-RESOLVED IN-SITU GISAXS STUDIES OF THE MESOSCOPIC ROUGHNESS DURING HOMOEPITAX-IAL ELECTRODEPOSITION ON AU(001)M. Ruge1, F. Golks1, P. Rajput2, J. Zegenhagen2, J. Stettner1, O.M. Magnussen11CAU-Kiel Institute of Experimental and Applied Physics - Solid State Physics, Leibnizstrasse 19, 24118 Kiel, Germany2European Synchrotron Radiation Facility, 6, rue Jules Horowitz, BP 220, 38043 Grenoble Cedex 9, FranceThe electrochemical deposition of metals is a subject of substantial basic research, motivated by current technologies, e.g.in the production of interconnects in microelectronic devices, as well as future applications. To obtain a better fundamentalunderstanding and get deeper insight into the elemental atomistic processes and the growth kinetics during deposition, thehomoepitaxial growth of Au on Au(001) in 0,1M HCl + 0.5mM HAuCl4 was investigated on the ID32 surface diffractometerat the ESRF by time resolved X-ray diffraction using a photon energy of 22,5 keV. A hanging meniscus transmission X-raycell, developed by our group, with minimized cell resistance and nearly unrestricted mass transport, enabled in-situ surfaceX-ray diffraction studies of rapid structural changes simultaneously with high quality electrochemical measurements. Theanalysis of 2D detector (dectris, Pilatus 300K-W) frame series allowed to monitor the 2D surface morphology evolutionduring kinetic roughening induced by the electrodeposition process with a time resolution of approximately 2 sec. In detail,differences have been found for the growth on reconstructed and unreconstructed Au(001) surfaces.Email of the presenting author: [email protected]


A33TIME-RESOLVED X-RAY DIFFRACTION STUDY OF LINBO3 UNDER PULSED EXTERNAL ELECTRIC FIELDRaphael Grifone1, Oleg Schmidt1, Semen Gorfman2, Ulrich Pietsch11Department of Physics, University of Siegen, Siegen, Germany.2Department of Physics, University of Warwick, Coventry, UK.Interaction of a crystal with a permanent external electric field is well known in form of macroscopic phenomena, suchas elastic deformation and converse piezoelectric effect. The atomistic origin of the corresponding physical properties ofsolids (elasticity and piezoelectricity) may be understood on the basis of precise investigations of the atomic movements in-duced by an applied electric perturbation. In our studies we investigated the response of ferroelectric LiNbO3 single crystalsto a perturbation caused by a pulsed external electric field. Using a stroboscopic like (modulation-demodulation) technique,involving periodic switching of the amplitude and direction of the applied field, which is described elsewhere [1]. For theperiodic modulation we switched a high voltage (HV) with U ∼ 1kV. To measure at the resonance frequency of the crystalsystem, the modulation frequency of the applied voltage is in the wide range of 1Hz - 10kHz. The time-dependent crystalresponse was studied by measuring ω-rocking curves of a few Bragg reflections. Sufficient statistics where collected by sum-ming up over about 106 succeeding HV cycles for each ω-angle of a rocking curve.We performed our experiment using a home lab X-ray source, with a high resolution four-circle diffractometer and an openpoint detector with a high counting rate. The samples were produced in a sandwich like structure with a 0.65mm thick z-cutLiNbO3 crystal plate covered by thin Gold contacts on both sights. Macroscopic bending mode vibrations of the specimencould be excited and visualised using Resonant Ultrasonic Spectroscopy (RUS) calculations. These bending modes are de-tected by time resolved X-ray diffraction from periodic oscillations of peak positions of near surface Bragg reflections. Dueto the [001] orientation of the crystal plate we probed two symmetric (00L) reflections quantitative but a few (H0L) (withL>H) reflections qualitative accessible in Bragg geometry. In addition, significant periodic variations of relative Bragg peakintensities could be resolved if the cycle frequency of external perturbation coincides with an eigenmode of macroscopicmechanical vibration of specimen.Changes in the order of 5% have been observed if the external E-field of 2kV/mm is switched within 200ns at cycle frequen-cies of 4.45kHz. Figure shows resonance case with the switching below. It is not clear yet what caused this intensity changesand the finding might be explained by several effects. The experiment opens the chance to detect the atomic response to anexternal elastic perturbation of a crystal.[1] S. Gorfman, O. Schmidt, M. Ziolkowski, M. von Kozierowski, U. Pietsch: J.Appl. Phys. 2010, 108Email of the presenting author: [email protected]

A34FIB INDUCED STRUCTURAL MODIFICATIONS IN THIN MAGNETIC FILMS.O. D. Roshchupkina1, J. Grenzer1, T. Strache1, M. Fritzsche1, A. Muecklich1, J. Fassbender11Helmholtz-Zentrum Dresden-Rossendorf e. V., Bautzner Landstrasse 400, GermanyFocused ion beam irradiation is a versatile tool that can be used for magnetic nanostructuring. In this work we compareboth FIB irradiation and a standard implantation taking into account their distinctive irradiation features. A 50nm thickpermalloy layer (Ni80Fe20) irradiated with different Ga+ ion fluences was used for the investigations. The structure wasstudied via XRD and EXAFS measurements carried out on the ESRF ROBL and ID01 facilities. Additionally TEM andmagneto-optic Kerr effect magnetometry were performed. Both types of irradiation demonstrate a similar behaviour: increas-ing the ion fluence causes a further material crystallization and a decrease of the magnetic moment. However FIB irradiationleads to a stronger crystallite growth due to the high current densities used.[1]C.M. Park and J. A. Bain., J. of Appl. Phys. 91, 6830 (2002).[2]W.M. Kaminsky et al., Appl. Phys. Lett. 78, 1589 (2001).Email of the presenting author: [email protected]


A35IN-SITU X-RAY SCATTERING: A TOOL FOR INVESTIGATION OF NANOSTRUCTURE FORMATIONJoerg Grenzer11Institute of Ion beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf e.V., P.O. 51 01 19; D-01314Dresden, GermanyNowadays, the development of new materials is often associated with specific properties of functionalized nanostructures.X-ray investigations are a very important tool to find the link between the functional (magnetism, luminescence) and the cor-responding structural properties (size, orientation etc.) that are generating this function and to explain the underlying physicalprocesses. This knowledge makes it possible to design new materials with specific properties. We report on (in-situ) X-raystudies that are focused on ion-beam sputtering techniques (IBS) creating nanostructures either by ion beam erosion or bysputter deposition processes. With IBS the roughness of solid surfaces can be modified on lateral scales of a few nanometersto micrometers or even further. In a defined parameter set IBS leads to a surface smoothing, whereas at other parameters theroughness is increased, leading eventually to periodic patterns, i.e. ripple and hexagonal dot patterns. In-situ measurementsof the surface roughness during IBS of GaSb surfaces give insight into the detailed mechanisms; especially, if the early timeregime is addressed.Modern synchrotron sources give us the possibility to study the nanostructure growth during deposition. A sputtering cham-ber mounted on a six-circle goniometer allows an insight into the growth of nanostructures using different scattering anddiffraction methods. We have investigated the growth of FePt islands incorporated into an Ag matrix. The high brillianceof the synchrotron source had made it possible to obtain a reliable GISAXS signal and to control the cluster morphologyduring growth even at the initial stage. By depositing 6 nm Ag layer directly on the SiO2 substrate, we obtained well definedFePt clusters. FePt nanoislands have been achieved without degradation of the magnetic properties. We obtained a magneticasymmetry with magnetic moments preferentially oriented parallel to the layer surface.[1] A. Keller, A. Biermanns, G. Carbone, J. Grenzer, S. Facsko, O. Plantevin, R. Gago, and T. H. Metzger, Applied PhysicsLetters 94, 193103 (2009).[2]V. Cantelli, J.v. Borany, N.M. Jeutter and ’and J. Grenzer, Adv. Eng. Mat 11(6), 480 (2009).Email of the presenting author: [email protected]

A36IN-SITU HIGH-TEMPERATURE INVESTIGATIONS OF THE INTERFACE REACTIONS IN NANOSCALEDCR/TA-C MULTILAYERS USING X-RAY SCATTERINGUlrike Ratayski1, David Rafaja1, Carsten Baehtz2, Hans-Joachim Scheibe3, Michael Leonhardt31Institute of Materials Science, TU Bergakademie Freiberg2Helmholzzentrum Dresden-Rossendorf3Fraunhofer Institute of Materials and Beam Technology IWSThe Cr/ta-C multilayers are regarded as diffusion barriers against the carbon diffusion from the functional ta-C coatingsinto the steel substrates. At the Cr/ta-C interfaces, chromium carbides are formed that have a narrow homogeneity range.Thus, they are expected to protect a further diffusion of carbon beyond the multilayer system. In order to get insights into thereactive diffusion kinetics in the Cr-C system on the nanoscale, in-situ X-ray scattering measurements were carried out at theBM 20 beamline at the European Synchrotron Radiation Facility (ESRF) in Grenoble. The interface reactions were visualizedvia changes in the layer thickness, interface roughness and interface morphology during a heat treatment in a temperaturerange between room temperature and 600C. Furthermore, the change of the electron density due to the heat treatment wasinvestigated. The electron density, the individual layer thickness and the interface roughness were obtained from the X-rayreflectivity measurements; additional information about the correlation of the interface corrugations came from the resonantsmall-angle diffuse scattering. The changes in the interface morphology were confirmed by TEM. These experiments werecomplemented by the reciprocal space mapping before and after the heat treatment. The influence of the initial nanostructureof the multilayers on the reaction diffusion process was investigated with the aid of multilayers having different individuallayer thicknesses and interface morphologies. The tetrahedrally bonded carbon (ta-C) layers were deposited at different ener-gies of the carbon ions. Their thickness varied between 6 and 10 nm. The Cr layer thickness was kept constant at 10 nm. Theinterface roughness varied between 5 and 15 Angstrm. After annealing the multilayers at 300C and 400C, a large increase ofboth, interface roughness and bilayer thickness, was observed that indicated development of intermediate phases in the Cr-Csystem. From the measurement of the electron density, it was deduced that even the metastable fcc-CrC forms at the Cr/ta-Cinterfaces. The formation of the metastable fcc-CrC was verified by HRTEM. The capability of the Cr/ta-C multilayers toserve as diffusion barrier was proven no degradation of the multilayers was observed after the annealing process.Email of the presenting author: [email protected]


A37IN-SITU X-RAY SCATTERING INVESTIGATION WITH HIGH RESOLUTION AT THE NANO BEAMLINE ATANKA DURING THE GROWTHS. Bauer1, Th. Schwarz1, A. Zimina1, S. Lazarev1, T. Baumbach11Instutut of Synchrotron Radiation, ANKA,Karlsruhe Institut of Technology (KIT) - Campus Nord, 76021 KarlsruheThe NANO beamline at the synchrotron source ANKA will be specialized on high-resolution x-ray diffraction, surface andinterface X-ray scattering investigations.One of the major interests is the real time monitoring of different growth processes, like e.g. of nano-particles, nanostructures,multilayers and superlattices. In order to carry out those in-situ measurements different types of environmental chambers canbe mounted on a heavy duty diffractometer which could support up to 500 kg and rotate the sample and its environmental inall directions in space. With two independent detection systems, both part of the diffractometer, the possibility to performsimultaneously two measurements will be available: Grazing Incidence Small Angle X-ray Scattering (GISAXS) to deter-mine the shape, size, position and correlation in nanostructures and Grazing Incidence Diffraction (GID) to characterise thesurface-patterned structure.A selection of cooperations and planned in-situ applications are presented, like e.g. Metal Organic Vapor Phase Epitaxy(MOVPE), Molecular Beam Epitaxy (MBE), Sputtering and Laser Processing. General parameters of interests are, e.g.:• Lattice parameters, chemical dependence of the elastic constants, relaxation degree and dislocations.• Structure and ordering of nanostructures like quantum dots or quantum wells.• Study of the structural changes and the mechanical characteristics of e.g. laser treated surface layers, emergence of newphases, grain size, texture or stress.• In-situ monitoring of oxide desorption and overgrowth.• In-situ annealing.• Understanding of growth modes in general.Email of the presenting author: [email protected]

A38REAL-TIME OBSERVATION OF STRUCTURAL AND OPTICAL CHANGES DURING FILM GROWTH OFEQUIMOLAR MIXTURES OF ORGANIC SEMICONDUCTORSK. Broch1, C. Frank1, A. Hinderhofer1, A. Aufderheide1, F. Anger1, A. Gerlach1, F. Schreiber11Institut fr Angewandte Physik, Universitat Tubingen, Auf der Morgenstelle 10, 72076 Tubingen, GermanyOrganic semiconductors have gained increasing attention in the last years due to their numerous applications in opto-electronic devices. Frequently, heterostructures of two different compounds (serving as electron donor and acceptor re-spectively) are used in order to produce layered or intermixed structures. In mixed films, interactions between two moleculespecies are usually important for the structural and optical properties. These are affected by the mixing behaviour of the twocomponents (intermixing on a molecular level vs. phase separation) as well as by possible charge transfer in the excited statebetween the molecules. Additionally, the properties of the system may change during film growth as contributions from thebulk outweigh interface effects with increasing film thickness [1]. We followed the growth of equimolar mixtures of sev-eral organic semiconductors in situ using X-ray reflectivity, grazing incidence X-ray diffraction and differential reflectancespectroscopy. Applying these techniques, we studied the structural and optical properties, in particular, the effect of inter-molecular interactions between the different molecular species on the properties of the mixed films. We present differentmaterial combinations, for example pentacene/perfluorinated pentacene, where we find evidence for intermixing on a molec-ular level [2] and pronounced changes in the optical spectra of the mixture, including a possible charge transfer betweendifferent molecules [3]. [1] U. Heinemeyer et al., Phys. Rev. Lett. 104 (2010), [2] A. Hinderhofer et al., J. Chem. Phys. 134(2011), [3] K. Broch et al., Phys. Rev. B. in printEmail of the presenting author: [email protected]

A39IN SITU GROWTH STUDIES OF N-ALKANES ON SILICA WITH REAL-TIME X-RAY METHODSC. Weber1, C. Frank1, S. Kowarik11

We investigate the growth behaviour of three different organic chain-molecules on silica, namely the n-alkanes n-hexatriacontane(C36H74), n-tetracontane (C40H82) and n-tetratetracontane (C44H90). The main focus lies on the influence of the chain-length of the organic molecules on the thin film growth. The growth process is monitored textitin situ by x-ray reflectivitywith an energy-dispersive detector. Fitting the experimental real-time data at several points in reciprocal space simultane-ously with a model based on the growth dynamics proposed by Trofimov et al. we are able to obtain information about thecritical layer coverages, the roughness and the downhill-transport rate of each layer at each point in time. A clear chain-lengthdependency of the latter physical parameters is found. Films formed by longer molecular chains roughen faster than filmsconsisting of shorter chains. The final films also exhibit specific chain-length-dependent differences. New unit cells arefound for n-tetracontane and n-tetratetracontane. All three systems form grain-like domains of lying-down molecules in thetop region of the film. The amount of those lambda-domains increases with increasing molecular chain-length. This result isobserved by x-ray reflectivity (XRR) and grazing incidence x-ray diffraction (GIXD).Email of the presenting author: [email protected]


A40FUNDAMENTALS AND APPLICATIONS OF GRAZING INCIDENCE X-RAY ABSORPTION SPECTROSCOPYDirk Lutzenkirchen-Hecht11Bergische Universitat Wuppertal, GermanyReflection mode grazing incidence X-ray absorption spectroscopy (GIXAFS) is a valuable tool for the in-situ investiga-tion of surface phenomena such as thin film growth, oxidation and reduction, etc. In the first part of this contribution, wewill discuss the fundamentals of X-ray absorption spectroscopy and especially GIXAFS, paying attention especially to theinfluence of surface and interface roughness on the resulting spectra, and consider the strength and limitations of this method.In addition, we will also discuss the experimental requirements for successful GIXAFS studies.Besides such fundamental aspects of reflection mode grazing incidence X-ray absorption spectroscopy, we will report onsome new applications of the technique in different scientific fields, for example in corrosion science, where the formationof thin oxide films on metals and the active dissolution (corrosion) of metals will be considered. Here GIXAFS is able toprovide detailed information on the structure of the oxide films under in-situ conditions. Such an electrochemical interfaceis also present in the case of Li-ion battery materials, where the insertion and extraction of the Li-ions can be followed as afunction of the electrode potential/charge.Furthermore, the useful application of the technique to reactive sputtering processes will be demonstrated - especially time-resolved experiments will be addressed. This way, structural information can be gained during the film growth without anyinterruption of the films deposition on time scales of some few seconds only. Newly developed experimental techniques evenallow to reduce the time resolution to the millisecond scale, thus giving access to an extremely detailed picture of the surfacestructure evolution. We will also report on thin metal films deposited on ultra-cold substrates (T<30 K), where the transitionof disordered amorphous films directly after deposition at those cryogenic temperatures to polycrystalline films can be studiedin-situ.The combination of grazing incidence X-ray absorption spectroscopy with non-specular X-ray scattering techniques allowsthe selective examination of interface structures. We will demonstrate the useful application of this new technique for theinvestigation of buried interfaces.Email of the presenting author: [email protected]

A41IN-SITU MEASUREMENTS OF SOLIDIFICATION OF POLY(3-HEXYLTHIOPHENE) SOLUTION DURING THEAPPLICATION OF AN EXTERNAL ELECTRIC FIELDL. S. Grodd1, S. Grigorian1, U. Pietsch11Solid State Physics, University of Siegen, GermanyConjugated polymers have attracted much attention during the past years. Especially poly(3-hexylthiophene) (P3HT) isin the focus of interest for applications in organic thin film transistors (OFETs) because of its rather high mobility and goodprocessability. The correlation of electrical and structural properties is crucial for understanding the processes taking placeinside the polymer film during device operation. Numerous studies are known investigating structure, morphology and elec-tric performance of solid thin films, e.g. [1-3]. In our study we focus on in-situ measurements of P3HT solution during thesolidification process under influence of an external electric field.The in-situ measurements of the structure were done in grazing incidence x-ray diffraction geometry using synchrotron ra-diation. Silicon substrates with oxide layer were prepared with source and drain gold electrodes of 2 mm channel length bythermal evaporation. Under helium atmosphere a solution of P3HT and chloroform was dropped onto the substrate while ap-plying fixed voltages between 0 V and 150 V to source and drain. Simultaneously to the measurement of current the intensityof the (100) or (020) peak was monitored by a 1D detector. Due to low scattering of the liquids the intensity of the structuralpeak drops down straight after droplet casting but increases during solvent evaporation reaching a level proportional to thedeposited P3HT material. During evaporation of the solvent the electrical current, which is on µA level, increases and quicklygetting its maximum straight before the structural peak has reached its final level. It is followed by exponential current de-crease at nearly constant structural peak intensity. Our findings reveal an importance not only of the crystalline fraction butwhole connecting network within polymer matrix.1 H. Sirringhaus, P. J. Brown, R. H. Friend, M. M. Nielsen, K. Bechgaard, B. M. W. Langeveld-Voss, A. J. H. Spiering, R. A.J. Janssen, E. W. Meijer, P. Herwig and D. M. de Leeuw, Nature, 401, 1999, 685-688.2 A. Zen, M. Saphiannikova, D. Neher, J. Grenzer, S. Grigorian, U. Pietsch, U. Asawapirom, S. Janietz, U. Scherf, I. Lieber-wirth, and G. Wegner, Macromolecules, 39, 2006, 2162-21713 R. Kline, M.D. McGehee, M. Toney, Nature Materials, 5, 2006, 222-228Email of the presenting author: [email protected]


A42GAP COLLECTOR DEVELOPMENT FOR SIGE HBT PERFORMANCE INCREASE: A HETEROSTRUCTUREGROWTH STUDYO. Skibitzki1, F. Hatami2, P. Zaumseil1, B. Dietrich1, Y. Yamamoto1, M.A. Schubert1, B. Tillack3, W.T. Masselink2, T.Schroeder11IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany2Humboldt Universitt zu Berlin, MNF1, Newtonstrasse 15, 12489 Berlin, Germany3Technische Universitt Berlin, HFT4, Einsteinufer 25, 10587 Berlin, GermanyTo develop a III/V wide band gap collector concept for future SiGe heterobipolar transistor (HBT) performance increase,a heterostructure growth study of GaP on pseudomorphic 4 off-oriented Si0.8Ge0.2/Si(001) substrates was performed. The-oretical model calculations were applied to evaluate the thermodynamic stability of pseudomorphic GaP/Si0.8Ge0.2/Si(001)heterostructures. A detailed structure and defect characterization study by x-ray diffraction (XRD), transmission electron mi-croscopy (TEM) and atomic force microscopy (AFM) is reported on single crystalline 170 nm GaP/20 nm Si0.8Ge0.2/Si(001).In line with theory, 20 nm Si0.8Ge0.2/Si(001) can be overgrown by GaP without affecting the pseudomorphism of thebase layer. The potential GaP heterostructure grows however partially relaxed, mainly due to defect nucleation at theGaP/Si0.8Ge0.2 interface. The achievement of 2D GaP growth conditions on Si0.8Ge0.2/Si(001) systems is thus a crucialstep for achieving fully pseudomorphic heterostructures.Email of the presenting author: [email protected]

A43X-RAY DIFFRACTION STUDY OF GAN/SC2O3/Y2O3/SI(111) HETEROSTRUCTURESL. Tarnawska1, P. Zaumseil1, P. Storck2, R. Paszkiewicz3, T. Schroeder11IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany2SILTRONIC AG, Hanns-Seidel-Platz 4, 81737 Munchen, Germany3WROCLAW UNIVERSITY OF TECHNOLOGY, Janiszewskiego 11/17, 50-372 Wroclaw, PolandGrowth of GaN on Si wafers is intensively pursued to provide high quality cost effective GaN virtual substrates for elec-tronic and optoelectronic applications. The direct deposition of GaN layers on Si presents, however, a big challenge due tohigh reactivity of the Si surface with nitrogen, large lattice mismatch, and large difference in thermal expansion coefficient.To solve these integration problems different semiconducting (e.g AlN, GaAs, ZnO) and insulating (e.g. α-Al2O3) bufferlayers were used in the past. In this work, we present a novel approach for the integration of GaN on Si(111) via Sc2O3/Y2O3bi-layer buffer system.The samples were grown in a multichamber molecular beam epitaxy system on 4-inch Si(111) wafers. To obtain completeinformation on the quality of GaN/Sc2O3/Y2O3/Si(111) heterostructures, RHEED, PL, XPS, XRR and XRD, SEM and TEMmeasurements were complemented by Synchrotron Radiation Grazing Incidence (SR-GI) XRD. Additionally, temperature-dependent XRD was performed to determine the coefficients of thermal expansion of buffer oxides and GaN. Our studiesshow that the Sc2O3/Y2O3 buffer approach on Si(111) provides a template of high structural quality for GaN overgrowth.Buffer oxides are of type-B stacking with respect to the Si(111) substrate and are fully relaxed. Sc2O3 and Y2O3 are ther-modynamically stable at least up to 900C what is sufficient for the GaN growth by MBE.Specular θ-2θ XRD scans show that the growth of single crystalline GaN on Sc2O3(111)/Y2O3(111)/Si(111) heterostructureis achieved. The in-plane orientation is GaN[10-10]//Sc2O3[2-1-1]//Y2O3[2-1-1]//Si[-211]. The main defects in 1000 nm-thick GaN layers are threading dislocations, with density in the order of 1010 cm-2, and stacking faults, resulting in cubicinclusions within the hexagonal matrix. These GaN cubic inclusions are formed mostly at the interface between GaN andSc2O3 and their contribution can be reduced by rapid thermal annealing of the heterostructure.Email of the presenting author: [email protected]

A44STRUCTURAL MODIFICATIONS INDUCED BY FIB IMPLANTATION IN MAGNETIC THIN FILMSO.D. Roshchupkina1, J. Grenzer1, T. Strache1, J. McCord1, M. Fritzsche1, A. Muecklich1, C. Baehtz1, J. Fassbender11Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden, GermanyRecently, there is a rise of interest in fabrication and investigation of nanometre sized magnetic objects. Magnetic prop-erties can easily be manipulated by ion beam implantation. Focused-ion beam (FIB) techniques are one way to combine bothnanopatterning and implantation. The main difference between standard ion implantation and FIB implantation is the beamcurrent density, which could lead to differences in the structural and magnetic properties. The aim of this work is to compareboth implantation techniques in terms of structural changes and to relate them to magnetic property changes.For our investigation we have used 50 nm thick non-ordered nano-crystalline permalloy (Ni81Fe19) films modified by a 30keV Ga+ ion beam. The magnetic properties were characterised via magneto-optic Kerr effect measurements at room tem-perature. Both types of implantation demonstrate a degradation of saturation magnetisation with increasing ion fluence. Forstructural investigations we have applied several techniques. We have used the advantage of non-destructive X-ray techniquesto study the structural changes. Besides X-ray diffraction, providing the long-range order information, EXAFS measurementsto probe the local structure were performed. Both methods are statistical ones, whereas TEM imaging provides informationon a local scale.Implantation leads to a crystallite growth from ∼12 nm up to ∼25 nm and further texturing of the materialtowards (111) direction at almost constant lattice parameter. In the case of FIB implanted samples the TEM images showcrystallites growing through the entire film at high implantation fluences. The EXAFS analysis shows an almost perfectnear-order coordination, corresponding to an fcc cell; only in the vicinity of the Ga atoms a small local deviation could beobserved. In general FIB and standard implantation demonstrate similar behaviour with a shift in the fluence value. Theseresults let us conclude that the simple presence of the Ga atoms is the dominating effect leading the degradation of saturationmagnetisation. Email of the presenting author:[email protected]


A45STUDYING THE STRUCTURE STOICHIOMETRY RELATIONSHIP OF MIXED CE2−XPRXO3+D (X = 0-2)OXIDE CATALYSTS ON SI(111) BY XRDM. H. Zoellner1, H. Wilkens2, J. Wollschlager2, P. Zaumseil1, T. Schroeder11IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.2Universitat Osnabruck, Barbarastr. 7, 49076 Osnabruck, Germany.Cerium and praseodymium oxides are of interest for catalytic applications as oxidative dehydrogenation, oxidative cou-pling and methane conversion. As single crystalline epitaxial films on a Silicon support, they can be used for model catalyticstudies. The oxides differ in their crystal structure and valence state. CeO2 exists in the cubic fluorite lattice with Ce4+.However, praseodymium prefers the 3+ state as Pr2O3, which has the cubic bixbyite or hexagonal lattice when grown onSi(111) in ultra-high vacuum (UHV). A mixture of both oxides enables to engineer the properties of the catalyst, e.g. oxygenstorage capacity (OSC), oxygen mobility and thermal stability, due to the improved redox reactivity and lattice alteration.The main objective here is to investigate the correlation between crystal structures and stoichiometries. Therefore, differentCe2−xPrxO3+d layers were grown on Si(111) with a hex-Pr2O3(0001) buffer layer by co-evaporating molecular beam epi-taxy (MBE). Reflection high energy electron diffraction (RHEED) was used to get a first insight into the layer orientation andits quality. X-ray photoemission spectroscopy (XPS) was performed in-situ after the growth to quantify the stoichiometries.Laboratory and synchrotron based X-ray diffraction (XRD) was carried out ex-situ to investigate the crystal structure andto observe a potential phase alteration or separation. Furthermore, the vertical and lateral lattice orientations were deter-mined and the strain status of the layers were analysed. This study revealed that Ce2−xPrxO3+d keeps the fluorite lattice forlow praseodymium concentrations. However, the lattice alters for medium and high concentrations to the bixbyite and evenhexagonal structure, respectively.Email of the presenting author: [email protected]

A46CHARACTERIZATION OF ORGANIC/INORGANIC INTERFACES BY X-RAY REFLECTIVITY AND TRANS-MISSION ELECTRON MICROSCOPYAlfred Neuhold1, Stefanie Fladischer2, Markus Neuschitzer1, Ingo Salzmann3, Elke Kraker4, Bernd Lamprecht4, WernerGrogger2, Roland Resel 1

1Institute of Solid State Physics, Graz University of Technology, Graz, Austria2Institute for Electron Microscopy, Graz University of Technology, Graz, Austria3Institut fur Physik, Humboldt Universitat zu Berlin, Berlin, Germany4JOANNEUM RESEARCH Forschungsgesellschaft mbH, Institute for Surface Technologies and Photonics, Weiz, AustriaOrganic light emitting diodes and photodiodes generally comprise organic-semiconductor thin-films with top metal elec-trodes. Several techniques exist for top-electrode formation on the organic layer including ion-beam sputtering (IBS), phys-ical vapour deposition (PVD) and electron-beam deposition (e-beam). These techniques generally are performed under vac-uum conditions and several preparation parameters like residual/partial gas pressure, deposition rate or substrate temperatureseverely impacts the growth of the metal electrodes. In this study the structural and morphological properties of thin filmsof the two prototypical semiconductors aluminium-tris(8-hydroxychinolin) (Alq3) and (4,7-diphenyl-1,10)-phenanthroline(Bphen) with Ag top electrodes are investigated on SiOx substrates comparing the above deposition techniques. PVD withvarying deposition rates was carried out at room temperature to form 20 nm thick electrodes on top of the nominally 50 nmthick organic films. X-ray reflectivity (XRR) and transmission electron microscopy (TEM) were used to assess the morphol-ogy at the organic/metal interface in dependence of the Ag deposition rate. It is found that at a deposition rate of 0.02 nm/sthe interdiffusion of Ag into Alq3 is significantly larger compared to a deposition rate of 1 nm/s. In addition, the Alq3/Aginterface roughness decreases with increasing deposition rate. In contrast, independent of the deposition rate, essentially nodiffusion of Ag clusters into the Bphen layer is observed, as evidenced by TEM. However, in this case XRR demonstrates asignificant increase of the Bphen/Ag interface roughness. The interdiffusion phenomenon of Ag into the subjacent organicthin film is rationalized by the different structural properties of the organic materials. The results obtained for PVD are com-pared to both e-beam and IBS deposited Ag electrodes.Email of the presenting author: [email protected]



Smolenice 2011 Notes


Smolenice 2011 Notes

ORGANIZERS:

Solid-State Physics Group, University of Siegen

Department of Condensed Matter Physics, Faculty of Mathematics and Physics,

Charles University in Prague

Department of Semiconductor Technology and Diagnostics, Institute of Electrical Engineering,

Slovak Academy of Sciences

Documents

8th Autumn School on X-ray Scattering from …kfkl.cz/Smolenice/images/programSmolenice_2011.pdfWe describe x-ray diffraction from thin ﬁlms consisting of monolayers with different