Point Defects in GaAs and Other Semiconductors

1992 ◽  
Vol 279 ◽  
Author(s):  
P. Ehrhart ◽  
K. Karsten ◽  
A. Pillukat
Keyword(s):  
Optical Absorption ◽  
Point Defects ◽  
Irradiation Dose ◽  
Ion Irradiation ◽  
Strongly Correlated ◽  
X Ray Diffraction ◽  
Defect Production ◽  
Annealing Stage ◽  
X Ray ◽  
Interstitial Atoms

ABSTRACTIn order to understand the properties of intrinsic point defects and their interactions at high defect concentrations GaAs wafers were irradiated at 4.5 K with 3 MeV electrons up to a dose of 4.1019 e-/cm2. The irradiated samples were investigated by X-ray Diffraction and optical absorption spectrocopy. The defect production increases linearly with irradiation dose and characteristic differences are observed for the two sublattices. The Ga-Frenkel pairs are strongly correlated and are characterized by much larger lattice relaxations (Vrel=2–3 atomic volumes) as compared to the As-Frenkel pairs (Vrel ≈ 1 at.voL). The dominating annealing stage around 300 K is attributed to the mobility of the Ga interstitial atoms whereas the As-interstitial atoms can recombine with their vacancies only around 500 K. These results are compared to those for InP, ZnSe and Ge. Implications for the understanding of the damage after ion irradiation and implantation are discussed.

scholarly journals The impact of point defects in n-type GaN layers on thermal decomposition of InGaN/GaN QWs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mikolaj Grabowski ◽  
Ewa Grzanka ◽  
Szymon Grzanka ◽  
Artur Lachowski ◽  
Julita Smalc-Koziorowska ◽  
...  
Keyword(s):  
Quantum Wells ◽  
High Temperatures ◽  
Point Defects ◽  
X Ray Diffraction ◽  
Helium Ions ◽  
X Ray ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
The Impact ◽  
Ingan Quantum Wells

AbstractThe aim of this paper is to give an experimental evidence that point defects (most probably gallium vacancies) induce decomposition of InGaN quantum wells (QWs) at high temperatures. In the experiment performed, we implanted GaN:Si/sapphire substrates with helium ions in order to introduce a high density of point defects. Then, we grew InGaN QWs on such substrates at temperature of 730 °C, what caused elimination of most (but not all) of the implantation-induced point defects expanding the crystal lattice. The InGaN QWs were almost identical to those grown on unimplanted GaN substrates. In the next step of the experiment, we annealed samples grown on unimplanted and implanted GaN at temperatures of 900 °C, 920 °C and 940 °C for half an hour. The samples were examined using Photoluminescence, X-ray Diffraction and Transmission Electron Microscopy. We found out that the decomposition of InGaN QWs started at lower temperatures for the samples grown on the implanted GaN substrates what provides a strong experimental support that point defects play important role in InGaN decomposition at high temperatures.

Energy Band Gap Studies of CdS Nanomaterials

2008 ◽  
Vol 3 ◽  
pp. 97-102 ◽  
Author(s):  
Dinu Patidar ◽  
K.S. Rathore ◽  
N.S. Saxena ◽  
Kananbala Sharma ◽  
T.P. Sharma
Keyword(s):  
Optical Absorption ◽  
Band Gap ◽  
Energy Band ◽  
Chemical Method ◽  
Optical Absorption Spectroscopy ◽  
Cds Nanoparticles ◽  
X Ray Diffraction ◽  
Energy Band Gap ◽  
X Ray ◽  
Simple Chemical

The CdS nanoparticles of different sizes are synthesized by a simple chemical method. Here, CdS nanoparticles are grown through the reaction of solution of different concentration of CdCl2 with H2S. X-ray diffraction pattern confirms nano nature of CdS and has been used to determine the size of particle. Optical absorption spectroscopy is used to measure the energy band gap of these nanomaterials by using Tauc relation. Energy band gap ranging between 3.12 eV to 2.47 eV have been obtained for the samples containing the nanoparticles in the range of 2.3 to 6.0 nm size. A correlation between the band gap and size of the nanoparticles is also established.

Uranium–molybdenum nuclear fuel plates behaviour under heavy ion irradiation: An X-ray diffraction analysis

2009 ◽  
Vol 385 (2) ◽  
pp. 449-455 ◽  
Author(s):  
H. Palancher ◽  
N. Wieschalla ◽  
P. Martin ◽  
R. Tucoulou ◽  
C. Sabathier ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
Nuclear Fuel ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heavy Ion Irradiation

scholarly journals X-ray diffraction and thermodynamics kinetics of SiB6 under gamma irradiation dose

Silicon ◽  
2018 ◽  
Vol 11 (5) ◽  
pp. 2499-2504 ◽  
Author(s):  
M. N. Mirzayev ◽  
S. H. Jabarov ◽  
E. B. Asgerov ◽  
R. N. Mehdiyeva ◽  
T. T. Thabethe ◽  
...  
Keyword(s):  
Gamma Irradiation ◽  
Irradiation Dose ◽  
X Ray Diffraction ◽  
X Ray ◽  
Kinetics Of

Crystallization Process and Chemical Disorder in Flash Evaporated Amorphous Gallium Antimonide Films

1993 ◽  
Vol 321 ◽  
Author(s):  
J. H. Dias Da Silva ◽  
I. Cisneros ◽  
L. P. Cardoso
Keyword(s):  
Optical Absorption ◽  
Absorption Edge ◽  
Gallium Antimonide ◽  
Crystallization Process ◽  
Optical Absorption Edge ◽  
X Ray Diffraction ◽  
Flash Evaporation ◽  
X Ray ◽  
Local Ordering ◽  
Chemical Disorder

ABSTRACTIn this work we describe a flash evaporation system specially built to produce Amorphous films of III-V compounds and characterize GaSb films using optical, electrical and X-Ray diffraction Measurements. Changes in the composition of the GaSb samples were obtained by the use of different crucible temperatures. In such samples, consequently, the optical absorption edge and the DC electrical conductivity were Modified. The departure from stoichiometry in GaSb films is analyzed on the basis of these results which can be used as an evidence of the chemical disorder. This kind of disorder is represented by either wrong bonds or sites with different coordination.Thermal annealing with a sequence of increasing temperatures first induced detectable variations in the optical absorption edge and in the vibrational properties of the Amorphous GaSb. These variations are compatible with the GaSb local ordering and were observed by Raman scattering and infrared absorption spectra. The annealing at higher temperatures allowed the crystallization of the material confirmed by X-Ray diffraction. From these experimental results a crystallization mechanism based on the segregation of Sb excess coming from the crystallized regions toward the Amorphous tissue is proposed.

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