Exploring Different Atomic Force Microscopy Probes...Exploring Different Atomic Force Microscopy Probes Sergei Magonov Group/Presentation Title Agilent Restricted Page 1 Month ##,

Exploring Different Atomic Force Microscopy Probes

Sergei Magonov

Group/Presentation TitleAgilent Restricted

Month ##, 200XPage 1

Agilent Web-Seminar October 18 2007

Outline

1. Regular and High-Resolution AFM Probes

2. Approaching True Molecular/Atomic Resolution in AFM

3. AFM Probes for Measurements of Local Mechanical, Electric and Thermal Properties




Regular and High-Resolution Silicon ProbesRegular Si Probes

Carbon Spike Tungsten SpikeCNT-Probes

High-Resolution Probes




Bottom images – courtesy of MikroMasch

Carbon SpikeSi waferRegular Si tip

Effect of Tip Sharpness in Imaging of Nanoscale Structures

10 nm 1 3 nm10 nm 1-3 nm

RNA-Based NanostructuresRegular Si tip Carbon Spike

Cooperation with A



150 nm150 nmCooperation with A. Koyfman (UCSB)


Polydiacetylene crystal, PDA TY

Contact mode in airMolecular Resolution in Atomic Force Microscopy

T2TX

Y

Magonov S et al Polym

bc Tx

Ty

0.49 c 1.41

Magonov S. et al Polym. Bull. 1991, 26, 223

nm1.41 nm 8.5 nm

Si (7×7) F. Giessibl, Science 1995, 267, 68

Frequency Modulation in UHV, air, liquid

H. Yamada group (Kyoto University) PDASAMY. Sugawara et al Science 1995, 270, 1646

6



5.5 nm6 nm

APL 2005, 86, 034101; 193108


Molecular Resolution in Atomic Force Microscopy

Amplitude Modulation i i

Polydiacetylene crystal, PDA

in air

Veeco D5000 +

D. Klinov, S. Magonov APL 2004, 84, 2697

20 nm 15 nmNSIIIA/Extender

Amplitude Modulation in air

Polydiacetylene crystal, PDA

Agilent 5500 microscope

15 nmLow thermal drift of AFM microscope is the key feature for high-resolution



microscope23 nm


y gimaging in amplitude modulation mode.

Simulation of Imaging of PDA in Amplitude Modulation Mode

Low-force imaging of the

R = 0.15 nm R = 5 nm R = 100 nm

Low force imaging of the perfect PDA lattice with tips of different size (R – radius)

corrugations ~ 0.01 nmcorrugations ~ 0.03 nmcorrugations ~ 0.2 nm

Imaging of the perfect PDA lattice with a tip (R = 5 nm)

Force increases (Asp decreases) ->

at different set levels of tip-sample force (different set-point amplitudes, Asp)

Imaging of the defect PDA lattice with tips of different i (R) d diff t f

R = 0.15nm; Asp = 20 nm R = 1nm; Asp = 19 nm R = 5nm; Asp = 18 nm

S. Belikov & S. Magonov, Jap J Appl Phys 45 (2006) 2158;

size (R) and different forces (Asp).



S. Magonov & S. Belikov www.nanohub.org/resources/2030/


1 2 4Single diamond probe before imaging After AFM imagingImaging of etched Al

Optimization of Imaging in Oscillatory Mode: Wear of Tip Apex

1 2 4

MicroStar

3R3=10nm

Si probe before imaging After imaging polymer (E~2GPa) After imaging etched Al

TechnologiesR3=14nm

Cooperation ith Bernard Mesa



Probe stiffness k=0.6 N/mCooperation with Bernard Mesa (MicroStar Technologies)


Team-Nanotec

Effect of Tip Sharpness in Imaging of Nanoscale Structures

T N t

Olympus Team-Nanotec

Team-Nanotec

Sharp probe Spherical probe

76 nm10 nm

34 nm 35 nm



1 μm 1 μm


Electrochemically etched Pt/Ir probe Mechanically sharpened Pt/Ir probe Sharpened Pt/Ir probe (MST)Probes for Scanning Tunneling Microscopy

Probes for Electric Measurements in Scanning Probe Microscopy

Commercial SiO2 with Pt coating Conducting Single Diamond Probe (MST)Probes for Electric Force Microscopy



MST – MicroStar Technologies


Electric Force Microscopy with Diamond/Sapphire ProbesSingle diamond tip

S hiSapphire cantilever

Conducting Si probe Conducting diamond probe

1. A sapphire cantilever with a semi-circular cross-section eliminates optical interference common for commercial

Mesa B Magonov S J Physics

probes.

2. Long diamond tip (~100 μm) reduces damping of Q-factor.



Mesa B., Magonov S. J. Physics Conf Ser 2007, 61, 770


Micromachined Thermal Probes

Introduction to Nano-TA

Infrared Microscopy

200 μm200 μm




Courtesy of Kevin Kjoller (Anasys Instruments)

AFM Probe for Measurements of Time-Varying Nanomechanical Forces Flexural Vibration

Spectrum Torsional Response

Flexural Response

Torsional Vibrational Spectrum

Force-vs.-Time

1. Imaging at high harmonicsForce-vs.-Distance

Topography Phase 10th Harmonic

85C

2. Mapping of mechanical properties during scanning in amplitude modulation mode

115C

Height Phase

7 μm

Elastic modulus145C

160C




O. Sahin et al Nature Nanotechnology 2007, 226, 1038.

ConclusionsLow-force imaging with atomic-size probes is the ultimate goal of AFMLow-force imaging with atomic-size probes is the ultimate goal of AFM because it provides true sample topography and true molecular/atomic resolution. At the moment, limitations of the tip-force control and tip sharpness restrict image resolution. Joint efforts of instrument and probesharpness restrict image resolution. Joint efforts of instrument and probe developers are needed for further progress in high-resolution imaging.

In practical purposes, a characterization of AFM probe (performed by a probe manufacturer or by user) is invaluable for their optimal choice thatprobe manufacturer or by user) is invaluable for their optimal choice that depends on a particular application. For many applications, probes with a round-shaped tip (with known and not necessary small diameter) might be more rational than a use of sharp probesmore rational than a use of sharp probes.

AFM value is also increasing due to expanded capabilities of mapping mechanical, electric and thermal properties. These applications require a large variety of the probes in which specific properties should be in interplaylarge variety of the probes, in which specific properties should be in interplay with the cantilever and tip geometries, and this field demands increasing attention.




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Exploring Different Atomic Force Microscopy Probes...Exploring Different Atomic Force Microscopy Probes Sergei Magonov Group/Presentation Title Agilent Restricted Page 1 Month ##,