Instrumentation at Nanostructure Physics, KTH

Rayuta Yagi, Anders Liljeborg, Jochen Walter, Mattias Urech, David HavilandPeter Ågren, Jan Johansson, Jonas Rundqvist, Karin Andersson, Silvia Corlevi

(not shown – Vladislav Korenivski)

Our Realm in Experimental Physics

• Low energies (eV)

• Low Temperatures (20 mK)

• Small signals (nV, fA)

• Single charge (2e=1.3x10-18 C)

• Single flux quanta (0=2.06x10-15 W m2)

• Small dimensions (10 – 100 nm)

Typical Sample and Measurement

-30

-20

-10

0

10

20

30

-400 -200 0 200 400

I (pA)

V (µV)

B = 57 G

B = 66 G

B = 70 G

T=50mK

KTH Nano-Fab Lab

•Nano and micro scale fabrication,imaging and metrology•Joint laboratory facility, broad user spectrum•Graduate students are users•Low overhead costs, flexible research environment

Philosophy

K. A. Wallenberg Foundation

9 Msek, 1998•Electron-beam lithography•Plasma RIE•Wire bonder•clean benches, spinner, microscope, etc.

10 Msek , 2001•Atomic Force Microscope•Plasma RIE•Surface profilometer•photo lithography•clean benches

Low Cost (semi) clean room environment

E-beam lithography

Surface Profilometer

Atomic Force Microscope

Vacuum Deposition

System

Laminar flow benches(spinner, development)

Wet bench, hood

Light Microscope

Phase 2 Instruments – Phase 1 Instruments

Wire Bonder

Photo Lithography

Reactive IonEtcher(s)

Fluorescence MicroscopeCooled CCD camera

Low cost clean (enough) environment500 – 2000 particles per cubic foot

Ventilated clean air hoodsparticle count < 1/ft.3 after 2 minutes

Electron beam lithography•Versatile research tool•Beam writing and SEM capability, 6 inch laser stage.•High resolution (slow, nano features) and Low Resolution (fast, micro structure)

RaithTurnkey 150

Thickness measurement

0.1 Å vertical resolution0.5 m horizontalLow force (ca. N?)

Scanning Probe Microscope

Nanoscope IV Multi-mode: •AFM (air, liquid)•STM (air)•MFM, ESFM etc.•Image surface•Force measurement

spin dependant transport in nano-scale junctions(Nanostructure Physics, KTH)

-400 -200 0 200 400

0

5

10

Left junction Right junction

MR (%)

Field (Oe)

Two closely spacedCo/AlOx/Co tunnel junctions

Room TemperatureMagneto-resistance (MR)

Superconducting nano-circuits as quantum bits(Nanostructure Physics, KTH; Quantum Field Theory, SU)

GateSQUID

SETelectrometerAl Tunnel

junction

Aulead

Nanostructured ferroelectrics for linear and nonlinear optics(Laser physics and quantum optics, KTH)

Photonic Bandgap Structures

ion-exchanged gratings in KTP = 800 nm, depth > 200 m • aspect ratio > 500:1• L= 2 mm, w=1mm

used as passive narrow band filters

Active devices – electrically addressable filters

sub-micron periodically domain inverted

structures fabricated for first time• = 720 nm, depth 500 m • aspect ratio > 500:1• L=1 mm, W= 1 mm

Top view

Bottomview

Nano fabricated X-ray lenses(Biomedical and X-ray Physics, KTH)

Diffractive Optics -- Zone PlateCompact X-ray Microscope

Nano-patterned surfaces for cell growth studies(Polymer Chemistry, KTH; Nanostructure Physics, KTH)

Optical microscope imageSine-wave grooves in PMMA

Electron-microscope image

Protein A cys - biotin - neutravidin fluoro spheres self assemble on nanometer scale pattern(Nanostructure physics, KTH, Protein Engineering, KTH)

Neutravidin

40 nm fluorescent sphere

S-H PEG 50 Å

Au 2000 Å

10 m

Measurement Equipment

• Low Temperatures (down to 20 mk)

• High Frequency (up to 2 GHz)

• Small Signals (fA, nV, Lockin, low noise AF)

• High Impedence (> G Ohm)

Low Temperature

Dilution Refrigerator (Tmin 250 mK)

He3 Crostat (Tmin 250 mK)

Low Frequency techniques

• Lockin Amplifier• Low noise preamplifiers

– Home-made based on BB OPA111, high source impedence, high CMR, symmetric baising circuit.

– Standford 560 (voltage) and 570 (current) preamps

• Noise Matching – match source impedance to input impedence of preamp at given frequency for minimum noise

Network Analyizer up to 2GHz

Reflected and transmitted signal, Amplitude and phase

•Impedance of high inductance microstrips•Permiability of magnetic films•Characterize transmission lines, couplings, filters

No picture - Digital Sampling Oscilloscope with TDR module (ps resolution)

Vibrating Sample Magnetometer

M vs. H of this magnetic filmsAlso “loop tracer”, real time rotation in plane of film

Magneto-optical Kerr Effect

Future HF Techniques

• ns or sub-ns rise time pulses

• Broadband cabling in to cryostat

• CW generator greater than 2 GHz

• AWF generator

• Pulsed RF

• Field calculations around microstrips

• Tricks …. opto-electric? ……