scholarly journals Structural Transformations in self-assembled Semiconductor Quantum Dots as inferred by Transmission Electron Microscopy

2002 ◽  
Author(s):  
Peter Mock ◽  
Yuanyuan Lei ◽  
Teya Topuria ◽  
Nigel D. Browning ◽  
Regina Ragan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Structural Transformations ◽  
Semiconductor Quantum Dots ◽  
Transmission Electron ◽  
Self Assembled

Microstructures and Growth Characteristics of Self-Assembled InAs/GaAs Quantum Dots Investigated by Transmission Electron Microscopy

2007 ◽  
Vol 26-28 ◽  
pp. 1207-1210
Author(s):  
Hyung Seok Kim ◽  
Ju Hyung Suh ◽  
Chan Gyung Park ◽  
Sang Jun Lee ◽  
Sam Kyu Noh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Chemical Potential ◽  
Early Stage ◽  
Compressive Strain ◽  
Potential Gradient ◽  
Growth Direction ◽  
Transmission Electron ◽  
Self Assembled

The microstructure and strain characteristics of self-assembled InAs/GaAs quantum dots (QDs) were studied by using transmission electron microscopy. Compressive strain was induced to uncapped QDs from GaAs substrate and the misfit strain largely increased after the deposition of GaAs cap layer. Tensile strain outside QD was extended along the vertical growth direction; up to 15 nm above the wetting layer. Vertically nonaligned and aligned stacked QDs were grown by adjusting the thickness of GaAs spacer layers. The QDs with a lens-shaped morphology were formed in the early stage of growth, and their apex was flattened by the out-diffusion of In atoms upon GaAs capping. However, aligned QDs maintained their lens-shaped structure with round apex after capping. It is believed that their apex did not flatten because the chemical potential gradient of In was relatively low due to the adjacent InAs QD layers.

Transmission electron microscopy of semiconductor quantum dots

2000 ◽  
Vol 199 (2) ◽  
pp. 130-140 ◽  
Author(s):  
C.-P. Liu ◽  
P. D. Miller ◽  
W. L. Henstrom ◽  
J. M. Gibson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Semiconductor Quantum Dots ◽  
Transmission Electron

Determination of the size, shape, and composition of indium-flushed self-assembled quantum dots by transmission electron microscopy

2000 ◽  
Vol 88 (5) ◽  
pp. 2272-2277 ◽  
Author(s):  
J. P. McCaffrey ◽  
M. D. Robertson ◽  
S. Fafard ◽  
Z. R. Wasilewski ◽  
E. M. Griswold ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Transmission Electron ◽  
Self Assembled

Limits and Properties of Size Quantization Effects in InAs Self Assembled Quantum Dots

1996 ◽  
Vol 452 ◽  
Author(s):  
K. H. Schmidt ◽  
G. Medeiros-Ribeiro ◽  
M. Cheng ◽  
P. M. Petroff
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Size Quantization ◽  
Island Growth ◽  
Growth Regime ◽  
Photocurrent Spectroscopy ◽  
Transmission Electron ◽  
Self Assembled ◽  
Energetic Position

AbstractIn this paper we report on the limits and properties of size quantization effects in InAs self assembled quantum dots (QDs). Size, density and character of the InAs islands are investigated by transmission electron microscopy. The electronic and optical properties of the islands in the coherent and dislocated growth regime are studied using capacitance, photoluminescence, photovoltage and photocurrent spectroscopy. In the data measured with the different techniques, the change in dot size and density as well as the transition from coherent to dislocated island growth is clearly observable. An increasing QD size causes a red shift in the energetic position of the QD features while the density of the islands is reflected in the intensity of the QD signal. The decrease in intensity at high InAs coverage is attributed to dislocated island formation.

Sign in / Sign up

Export Citation Format

Share Document