Semiconductor nanoheterostructures in nonequilibrium conditions: glance through

scanning probe microscope

K.S. Ladutenko (SPbGPU)

scientific advisers

V.P. Evtikhiev and A.V. Ankudinov

Ioffe Institute

Plan of the report:

• The construction of atomic force microscope

• Several techniques

• My research of nanoheterostructures in nonequilibrium conditions

The construction of atomic force microscope

• Probe

• “Probe-sample” interaction detection system

• Coarse positioning system

• Fine positioning system (piezoelectric tube)

• Feedback loop

• Vibration isolation system

The outward appearance

our microscope

Smena NT-MDT

Coarse positioning system

• Arm reducer.

• Springing reducer

• Piezo stepper motor • Stepper electric motor

Piezoceramic scanner

kijkij Edu Uh

ldZ 0

Piezoceramics drawbacks

1. Nonlinearity

2. Creep

3. Hysteresis

1

2 3

Probe

Van der Waals interaction

“Probe-sample” interaction detection system

FFzz

FFLL

“Probe-sample” interaction detection system

Feedback loop

Vibration isolation system

Hz

Hz

ext 10020

1010

Acoustic noises

Measuring techniques

• contact techniques – constant force technique – constant height technique – lateral force technique

• Semicontact – constant amplitude technique – Kelvin probe technique

Constant force technique

Constant height technique

Lateral force technique

GaSb with five quantum wells GaInSbAs GaInSbAs(5nm)/GaSb(25nm)

QW QW

Constant amplitude technique

Kelvin probe technique

)sin( tVVV acdctip

dz

dCyxVF tipcap

2),(2

1

dz

dCtVΦ(x,y)VF acdccap )sin()(

List of techniques STM techniques • Constant Current mode

• Constant Height mode

• Barrier Height imaging

• Density of States imaging

• I(z) Spectroscopy

• I(V) Spectroscopy

AFM techniques• dc Contact techniques

• Constant Height mode

• Constant Force mode

• Contact Error mode

• Lateral Force Imaging

• Spreading Resistance Imaging

• ac Contact techniques

• Force Modulation mode

• Contact EFM

• AFAM

• AFAM Resonance Spectroscopy

• Piezoresponce Force Microscopy

• Semicontact techniques • Semicontact mode • Phase Imaging mode • Semicontact Error mode • Non-Contact techniques • Non-Contact mode • Frequency Modulation mode

• Many-pass techniques • EFM • Scanning Capacitance

Microscopy • Kelvin Probe Microscopy • DC MFM • AC MFM • Dissipation Force Microscopy

• Spectroscopies • Force-distance curves • Adhesion Force imaging • Amplitude-distance curves • Phase-distance curves • Frequency-distance curves • Full-resonance Spectroscopy

SNOM techniques • Shear Force Microscopy • Transmission mode • Reflection mode • Luminescence mode • SNOM Lithography

aSNOM techniques • Scanning Plasmon Near-field

Microscopy

Lithographies • AFM Oxidation Lithography • STM Lithography • AFM Lithography - Scratching • AFM Lithography - Dynamic

Plowing

Confocal Microscopy techniques • Laser mode • Image mode • Spectral mode • Confocal Volume Lithography

Semiconductor nanoheterostructure in nonequlibrium conditions

• The motivation : need to improve the characteristics of injection lasers

• Method : Kelvin probe technique

• Modernization of this method

• Results

• Conclusions

Motivation

N P

h

p i n

Technique to measure the leakage currants

h

Measurement

CPD dependence from pumping currantV

olta

ge, V

Vol

tage

, V

X, nmX, nm

Impulse power supply

p i n

Technique to measure the leakage currants

CPD dependence from pumping currantV

olta

ge, V

Vol

tage

, V

Currant, ACurrant, A

Results

• The proposed and realized measurement procedure under pulse laser power supply allowed taking measurements at currents flowing through lasers is much higher than threshold current

• A change in contact potential difference is recorded far from pn-transition, in a strongly alloyed substrate depending on currents flowing through lasers

Conclusion

The attained results allow presuming that the proposed EFM procedure under pulse diode pumping enables to access the contribution of different physical processes to the leakage current of laser diode operating within a broad range of pumping currents.