PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

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PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES Kenneth Clark, John Colton , Matt Guerron, Dallas Smith, Scott Thalman Brigham Young University Haeyeon Yang Utah State University

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PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES. Kenneth Clark, John Colton , Matt Guerron , Dallas Smith, Scott Thalman Brigham Young University Haeyeon Yang Utah State University. Quantum Dots. GaAs. InGaAs. GaAs. Dong Jun Kim et al 2008 Nanotechnology 19 47560. - PowerPoint PPT Presentation

Transcript of PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

Page 1: PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

PHOTOLUMINESCENT PROPERTIES OF InGaAs

QUANTUM DOT STRUCTURES

Kenneth Clark, John Colton, Matt Guerron, Dallas Smith, Scott Thalman

Brigham Young University

Haeyeon Yang

Utah State University

Page 2: PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

Quantum Dots

Grown on surface with molecular

beams

Chemically grown in solution

http://uwnews.org/uweek/article.aspx?id=42599

GaAs

InGaAs

GaAs

Dong Jun Kim et al 2008

Nanotechnology 19 47560

Page 3: PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

Photoluminescence (P.L.)E

lec

tro

n E

ner

gy

Conduction Band

Valence Band

Band Gap

e e e e e e e e ee

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Spectroscopy

Detector

Monochromator

Mirror

Lenses

Focusing Lens

ChopperPower Controller

Cryostat

Lock-in Amplifier

BNC Cable

Sample

Page 5: PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

1000 1200 1400

1E-11

1E-10

1E-9

P.L. (Arbitrary Units)

Wavelength (nm)

50 mW

032607B, 3.7K, 50% Duty, 3s Tau, 780nm

The Experiment

W. Chang et al (1999 )

Quantum Dots

Wetting Layer

Indium Rich

Regions

Wavelength

Page 6: PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

Scan Results

Problem: Peaks shift giving

Inaccurate scan results.

Reason: Higher excitation energy

causes sample heating.800 1000 1200 1400

1E-11

1E-10

1E-9

160mW80mW

P.L (arb. units)

Wavelength (nm)

250mW

Laser at 780nm

Sample 032607B

230mW240mW

Page 7: PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

The Solution

Duty Cycle decreased from 50% to 8.33%

Page 8: PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

800 1000 1200 1400

1E-11

1E-10

1E-9

160mW80mW

P.L (arb. units)

Wavelength (nm)

250mW

Laser at 780nm

Sample 032607B

230mW240mW

1000 1200 1400

1E-12

1E-11

Power (Arbitrary Units)

Wavelength (nm)

120mW (889.5W/cm^2)160mW (1186W/cm^2)200mW (1482.6W/cm^2)260mW (1927.4W/cm^2)

Sample 032607B, 3K, 780nm, 8% Duty, .3s Tau Files 8,9,12,13

Less signal, meaning lower

intensity readings.

Ability to use higher

Excitation energies

Page 9: PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES
Page 10: PHOTOLUMINESCENT PROPERTIES OF InGaAs QUANTUM DOT STRUCTURES

In Conclusion

100nm

Yang et al., submitted to Nanoletters

These samples have strong P.L. Adjust growth technique

800 1000 1200 1400 1600 1800

0.00

0.02

0.04

0.06

0.08

0.10

P.L. (V)

Wavelength (nm)

Light Source: 780nm, 50 mW

Detector: PDF 10C

Chop: 20 Hz, 50% Duty

Spec: Grating C

Lock-in: V-mode, tau=0.3s

File 2

September 9, 2010 Sample 032607B

P.L. up to 1400nm even at

room temperature

Patterned samples