Band Edge Optical Absorption of Molecular Beam Epitaxial GaSb Grown on Semi-Insulating GaAs Substrate

1993 ◽  
Vol 325 ◽  
Author(s):  
M. Shah ◽  
M.O. Manasreh ◽  
R. Kaspi ◽  
M. Y. Yen ◽  
B. A. Philips ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Optical Absorption ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Free Exciton ◽  
Buffer Layers ◽  
Band Edge ◽  
Exciton Absorption ◽  
Molecular Beam Epitaxial ◽  
Gaas Substrates

AbstractThe optical absorption of the band edge of GaSb layers grown on semi-insulating GaAs substrates by the molecular beam epitaxy (MBE) technique is studied as a function of temperature. A free exciton absorption peak at 0.807 eV was observed at 10 K. The free exciton line is observed in either thick samples (5μm thick) or samples with ∼0.1 μm thick AlSb buffer layers. The latter samples suggest that the AlSb buffer layer is very effective in preventing some of the dislocations from propagating into the MBE GaSb layers. The fitting of the band gap of the GaSb layers as a function of temperature gives a Debye temperature different than that of the bulk GaSb calculated from the elastic constants.

Defects in HgCdTe grown by molecular beam epitaxy on GaAs substrates

2012 ◽  
Vol 20 (4) ◽  
Author(s):  
I. Izhnin ◽  
A. Izhnin ◽  
H. Savytskyy ◽  
O. Fitsych ◽  
N. Mikhailov ◽  
...  
Keyword(s):  
Optical Properties ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Buffer Layers ◽  
Structural Defects ◽  
Donor Concentration ◽  
Ion Milling ◽  
Electrical And Optical Properties ◽  
Gaas Substrates ◽  
Cdte Buffer

AbstractThe Hall effect and photoluminescence measurements combined with annealing and/or ion milling were used to study the electrical and optical properties of HgCdTe films grown by molecular-beam epitaxy on GaAs substrates with ZnTe and CdTe buffer layers. Unintentional donor doping, likely from the substrate, which resulted in residual donor concentration of the order of 1015 cm−3, was observed in the films. Also, acceptor states, possibly related to structural defects, were observed.

Molecular Beam Epitaxy of GaSb on GaAs Substrates with Compositionally Graded LT-GaAs x Sb 1- x Buffer Layers

2017 ◽  
Vol 34 (1) ◽  
pp. 018101
Author(s):  
Hai-Long Yu ◽  
Hao-Yue Wu ◽  
Hai-Jun Zhu ◽  
Guo-Feng Song ◽  
Yun Xu
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Buffer Layers ◽  
Gaas Substrates ◽  
Lt Gaas

Fabrication of CdTe Quantum Dot Arrays on GaAs utilizng Nanoporous Alumina Masks

2004 ◽  
Vol 818 ◽  
Author(s):  
Mi Jung ◽  
Hong Seok Lee ◽  
Hong Lee Park ◽  
Sun-Il Mho
Keyword(s):  
Molecular Beam Epitaxy ◽  
Quantum Dot ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Pore Density ◽  
Nanoporous Alumina ◽  
Gaas Substrates ◽  
Cdte Qds ◽  
Self Assembled ◽  
Cdte Quantum Dot

AbstractThe uniformity and reproducibility of the CdTe QD arrays on the GaAs substrates can be improved by using a nanoporous mask. The CdTe QDs on the GaAs substrate were grown by a molecular beam epitaxy (MBE) method. The nanoporous alumina masks used for the fabrication of QD arrays have the thickness from 0.3 νm to 5 νm with the nanochannels of ∼ 80 nm diameter and the pore density of ∼ 1010cm−2. When the thickness of the alumina mask used for the CdTe QD growth was about 300 nm, the CdTe QD arrays formed as a replica of the nanochannels of the mask. Smaller self-assembled CdTe QDs located randomly were produced by using the thicker nanochannel mask than 0.5 νm. The thickness of the nanochannel mask controls the size of the CdTe/GaAs QDs.

Interrelation between Strain Relaxation and InxAl1-xAs Compositional Graded Step Buffer Layers on GaAs Substrate Grown by Molecular Beam Epitaxy

2007 ◽  
Vol 124-126 ◽  
pp. 127-130
Author(s):  
Sook Hyun Hwang ◽  
Yu Mi Park ◽  
Hoon Ha Jeon ◽  
Kyung Seok Noh ◽  
Jae Kyu Kim ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Strain Relaxation ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Compositional Gradient ◽  
Transmission Electron ◽  
Two Samples ◽  
Compositional Gradients

We have grown delta-doped In0.5Ga0.5As /In0.5Al0.5As heterostructures on GaAs substrate applying with InxAl1-xAs compositional graded-step buffers, called metamorphic structures, grown by molecular beam epitaxy. Three types of buffer layers with different compositional gradients and thicknesses have designed to investigate the influence of the strain relaxation process. We characterized the samples by using transmission electron microscopy, triple-axis X-ray diffraction and Hall measurement. Two samples with different compositional gradient show almost same results in electrical properties. On the other hand, it is found that samples with different step thicknesses had shown the large differences in epilayer tilt and mosaic spread in the step-graded buffers. These results indicate that there exists an interrelation between the strain-relaxed buffer and 2DEG transport properties.

Anomalous Luminescence Properties of GaAs grown by Molecular Beam Epitaxy

1989 ◽  
Vol 163 ◽  
Author(s):  
I. Szafranek ◽  
M.A. Plano ◽  
M.J. McCollum ◽  
S.L. Jackson ◽  
S.A. Stockman ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Free Exciton ◽  
Donor Concentration ◽  
Sharp Line ◽  
Exciton Transition ◽  
Shallow Acceptor ◽  
Molecular Beam Epitaxial ◽  
Compensation Ratio ◽  
Transition Change

AbstractA shallow acceptor-like defect labeled “A” is frequently incorporated in molecular beam epitaxial GaAs. We report here anomalous photoluminescence effects that are induced by this defect. With increasing concentration of the “A” defect: (1) neutral and ionized donor-bound exciton peaks disappear almost completely even for donor concentration as high as 7×1014 cm-3 and compensation ratio ND/NA≈0.3; (2) a new, sharp line emerges at 1.5138 eV, and (3) the relative intensity and line shape of the free exciton transition change dramatically. These observations are discussed in the perspective of previous reports, where similar effects were, in our opinion, misinterpreted.

Molecular beam epitaxy of GaSb on GaAs substrates with AlSb/GaSb compound buffer layers

2010 ◽  
Vol 519 (1) ◽  
pp. 228-230 ◽  
Author(s):  
Ruiting Hao ◽  
Shukang Deng ◽  
Lanxian Shen ◽  
Peizhi Yang ◽  
Jielei Tu ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Buffer Layers ◽  
Gaas Substrates
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