scholarly journals Lattice Relaxation of the DX Centers in Ga1−x Alx As and of the Pressure–Induced Deep Donors in GaAs

1987 ◽  
Vol 104 ◽  
Author(s):  
M. F. Li ◽  
W. Shan ◽  
P. Y. Yu ◽  
W. L. Ransen ◽  
E. R. Weber ◽  
...  
Keyword(s):  
Deep Level ◽  
Lattice Relaxation ◽  
Transient Techniques ◽  
Large Lattice ◽  
Defect Energies ◽  
Deep Donor ◽  
Diamond Anvil ◽  
Dx Center ◽  
Capacitance Transient ◽  
Experimental Pressure

ABSTRACTDeep Level Transient Spectroscopies (DLTS) and capacitance transient techniques have been applied to GaAs:Si and to Ga1−xAlxAs:Te (x=0.35) under quasi-hydrostatic pressure using a diamond anvil cell. By substituting the experimental pressure coefficients of the defect energies into a model proposed by Li and Yu (Solid State Commun. 61, 13 (1987)) we concluded that both the DX center in the GaAlAs alloy and the pressure-induced deep donor (PIDD) in GaAs have large lattice relaxations associated with them.

scholarly journals The transformations of the EL6 deep level defect in n-GaAs: Is EL6 a DX-like center?

1998 ◽  
Vol 510 ◽  
Author(s):  
C.V. Reddy ◽  
S. Fung ◽  
C.D. Beling
Keyword(s):  
Deep Level ◽  
Lattice Relaxation ◽  
Persistent Photoconductivity ◽  
Charge Redistribution ◽  
Deep Level Defect ◽  
Native Defects ◽  
Large Lattice ◽  
Dx Center ◽  
Low Temperature Grown Gaas ◽  
Redistribution Effect

AbstractBased on the charge redistribution effect, as observed by the present authors, and the earlier reported large lattice relaxation and persistent photoconductivity phenomena associated with the EL6 defect seen in doped, undoped, semiinsulating(SI) and low temperature grown GaAs LT-GaAs), it is suggested that this defect be classified as a DX-center. A tentative unified atomic model is proposed for all the native defects EL2, EL3, EL5, and EL6 observed in GaAs.

Donor-like Deep Level Defects in GaN Characterized by Double-correlation Deep Level Transient Spectroscopy

2005 ◽  
Vol 892 ◽  
Author(s):  
Mo Ahoujja ◽  
M Hogsed ◽  
Y. K. Yeo ◽  
R. L. Hengehold
Keyword(s):  
Activation Energy ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Peak Intensity ◽  
Spectral Peaks ◽  
Deep Donor ◽  
Radiation Induced ◽  
Si Doped ◽  
Transient Spectroscopy ◽  
Capacitance Transient

AbstractSi doped GaN grown by molecular beam epitaxy on sapphire substrates were characterized by capacitance transient spectroscopy. Conventional deep level transient spectroscopy (DLTS) measurements displayed six deep level defects, labeled A1, A, B, C1, C, and D, with activation energy ranging from 0.20 to 0.82 eV below the conduction band. Based on the logarithmic dependence of the DLTS spectral peaks on the filling pulse width, it is deduced that the defects A, B, C, and D are concentrated in the vicinity of line dislocations. Double-correlation DLTS (DDLTS) measurements, on the other hand, showed that only defects A (0.82 eV) and D (0.22 eV) exhibited deep donor-like characteristics. Following a 1.0 MeV electron irradiation of the GaN sample, one radiation-induced peak, E, with activation energy less than 0.20 eV was observed in the DLTS spectrum. However, after annealing at 350 °C, this DLTS peak intensity was found to diminish significantly.

DX Center Analysis in Sn DOPED AlGaAs Layer of Double Heterostructures

1987 ◽  
Vol 104 ◽  
Author(s):  
M. Kaniewska ◽  
J. Kaniewski
Keyword(s):  
Thermal Activation ◽  
Lattice Relaxation ◽  
Electron Capture Cross Section ◽  
Final State ◽  
Al Content ◽  
Double Heterostructures ◽  
Algaas Layer ◽  
Large Lattice ◽  
Dx Center ◽  
Dlts Spectra

ABSTRACTCapacitance as well as photovoltage response methods have been used to analyse DX centers in the N–type AlGaAs:Sn layer of double heterostructures. DLTS spectra have revealed two deep traps. The first center (ΔE1 = 0.20eV) has been interpreted as the DX center related to Sn. In this paper, it is suggested that the second trap, with thermal activation energy equal to ΔE2 = 0.33eV, is also a DX center due to Sn, connected with another final state (the L minimum) of thermal processes. C-T characteristics and DLTS spectra have been compared with photovoltage spectra to find a correlation between the trap populations and Al content. The binding energy of the trap 2, as well as the temperature dependence of the electron capture cross-section, have been determined from measurements of the transition region width. Photoionization measurements confirm that there is large lattice relaxation when an electron is captured at the trap.

Deep Level Defects Related to Carbon Displacements in n- and p-Type 4H-SiC

2006 ◽  
Vol 527-529 ◽  
pp. 489-492 ◽  
Author(s):  
L. Storasta ◽  
Isaho Kamata ◽  
Tomonori Nakamura ◽  
Hidekazu Tsuchida
Keyword(s):  
Deep Level ◽  
Lattice Defect ◽  
Optical Trap ◽  
Conduction Band Edge ◽  
Energy Position ◽  
Transient Techniques ◽  
Low Energy Electron ◽  
P Type ◽  
Capacitance Transient ◽  
Trap Filling

We have investigated the electrically active deep level defects in p- and n-type 4H-SiC after low energy electron irradiation. Intrinsic defects were created by irradiation with 200 keV electrons, with energy sufficient to move only the carbon atoms in SiC lattice. Defect spectra were compared between the p- and n-doped samples prepared under identical irradiation conditions. We probed both conduction and valence band sides of the band-gap by using capacitance transient techniques with electrical and optical trap filling. We have found that the defect spectrum in the p-type epilayers differs significantly from the n-type. The Z1/Z2, EH1 and EH3 electron traps which are usually present in irradiated n-type material could not be detected in p-type samples. An electron trap at 1.6 eV below the conduction band edge is present in both n- and p-type samples at the same energy position and with similar concentration, therefore it is probably related to the same type of defect. We have also found a new hole trap in p-type epilayers at energy EV + 0.66 eV.

Deep Level Related Yellow Luminescence in P-Type GaN Grown by MBE on (0001) Sapphire

1999 ◽  
Vol 595 ◽  
Author(s):  
Giancarlo Salviati ◽  
Nicola Armani ◽  
Carlo Zanotti-Fregonara ◽  
Enos Gombia ◽  
Martin Albrecht ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Deep Level ◽  
Cubic Phase ◽  
Donor Level ◽  
Yellow Luminescence ◽  
Wurtzite Phase ◽  
Shallow Acceptor ◽  
Deep Donor ◽  
P Type ◽  
Deep Donor Level

AbstractYellow luminescence (YL) has been studied in GaN:Mg doped with Mg concentrations ranging from 1019 to 1021 cm−3 by spectral CL (T=5K) and TEM and explained by suggesting that a different mechanism could be responsible for the YL in p-type GaN with respect to that acting in n-type GaN.Transitions at 2.2, 2.8, 3.27, 3.21, and 3.44 eV were found. In addition to the wurtzite phase, TEM showed a different amount of the cubic phase in the samples. Nano tubes with a density of 3×109 cm−2 were also observed by approaching the layer/substrate interface. Besides this, coherent inclusions were found with a diameter in the nm range and a volume fraction of about 1%.The 2.8 eV transition was correlated to a deep level at 600 meV below the conduction band (CB) due to MgGa-VN complexes. The 3.27 eV emission was ascribed to a shallow acceptor at about 170-190 meV above the valence band (VB) due to MgGa.The 2.2 eV yellow band, not present in low doped samples, increased by increasing the Mg concentration. It was ascribed to a transition between a deep donor level at 0.8-1.1 eV below the CB edge due to NGa and the shallow acceptor due to MgGa. This assumption was checked by studying the role of C in Mg compensation. CL spectra from a sample with high C content showed transitions between a C-related 200 meV shallow donor and a deep donor level at about 0.9- 1.1 eV below the CB due to a NGa-VN complex. In our hypothesis this should induce a decrease of the integrated intensity in both the 2.2 and 2.8 eV bands, as actually shown by CL investigations.

Compositional Modulation and its Optoelectric Properties of Zn(S,Se,Te) Crystals Grown by Hydrogen Radical-Enhanced CVD

1995 ◽  
Vol 417 ◽  
Author(s):  
Hiroyuki Fujiwara ◽  
Toshihiro Ii ◽  
Isamu Shimizu
Keyword(s):  
Deep Level ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Small Shift ◽  
X Ray ◽  
Compositional Modulation ◽  
Peak Energy ◽  
Large Lattice ◽  
The Difference ◽  
Hydrogen Radical

AbstractHigh-quality (ZnS)n(ZnSe)12n and (ZnSe)n(ZnTe)11n (n=1∼4) crystals were grown at a low temperature of 200°C by hydrogen radical-enhanced chemical vapor deposition. From satellite peaks in x-ray diffraction spectra, these periodic structure crystals were confirmed to be grown coherently on substrates, in spite of large lattice mismatches between the grown layers and the substrates (͛=4∼7%). In photoluminescence (PL) spectra of these films, strong band-edge emissions were predominantly observed, resulting from a suppression of deep-level emissions. We found that the PL peak energy of (ZnSe)n(ZnTe)11n shifts systematically to lower energy by 200 meV with changes in the number of ZnSe layers (n), while relatively small shift of 13 meV was observed in (ZnS)n(ZnSe)12n. These discrepancy can be attributed to the difference of band-lineups or chemical natures of constituent atoms in these crystals.

Deep Donor and Acceptor Levels Induced by High Temperature and long time Annealing in LEC Gallium Arsenide

1991 ◽  
Vol 240 ◽  
Author(s):  
G. Marrakchi ◽  
A. Kalboussi ◽  
G. Guillot ◽  
M. Ben Salem ◽  
H. Maaref ◽  
...  
Keyword(s):  
High Temperature ◽  
Cold Water ◽  
Deep Level ◽  
Electron Trap ◽  
Single Donor ◽  
Long Duration ◽  
Donor And Acceptor ◽  
Deep Donor ◽  
Long Time ◽  
Lec Gaas

ABSTRACTThe effects of high temperature isothermal annealing on the electrical properties of donor and acceptor defects in n-type LEC GaAs are investigated. The annealing experiments are performed under As-rich atmosphere at 1000°C for 1–4 and 16 hours followed by a very quick quenching into cold water of the quartz ampoules containing the samples. The donor and acceptor levels are detected respectively by standard (DLTS) and optical (ODLTS) deep level spectroscopy. DLTS results show the presence of one single donor level present in unannealed and annealed samples at Ec - 0.79eV which is identified as the well known electron trap EL2 Only the sample annealed for 16 hs exhibits the presence of a new electron trap named TAI at Ec - 0.32eV. The appearance of TAI is correlated in one hand with the evolution of EL2 concentration and in the other hand to the effect of long duration (16 hs) of the treatment. For acceptor levels, two hole traps HT1 and HT2 are detected respectively at EV + 0.18 eV and EV+ 0.28 eV. HT1 is detected only in samples annealed for 4 and 16 hs and HT2 is detected in all studied samples. Photoluminescence (PL) measurements show the presence of the 1.44 eV band corresponding to gallium antisite GaAs defect. This band observed in unannealed and annealed samples shows that GaAs remains stable even after thermal annealing at lOOO°C for 16 hs and it is correlated with the presence of HT2.

Improvement of Local Deep Level Transient Spectroscopy for Microscopic Evaluation of SiO2/4H-SiC Interfaces

2018 ◽  
Vol 924 ◽  
pp. 289-292
Author(s):  
Yuji Yamagishi ◽  
Yasuo Cho
Keyword(s):  
Deep Level ◽  
Interface State ◽  
State Density ◽  
Trap States ◽  
Accurate Analysis ◽  
Microscopic Evaluation ◽  
Transient Spectroscopy ◽  
Capacitance Transient ◽  
Full Waveforms ◽  
Dimensional Mapping

We demonstrate our new local deep level spectroscopy system improved for more accurate analysis of trap states at SiO2/4H-SiC interfaces. Full waveforms of the local capacitance transient with the amplitude of attofarads and the time scale of microseconds were obtained and quantitatively analyzed. The local energy distribution of interface state density in the energy range of EC − Eit = 0.31–0.38 eV was obtained. Two-dimensional mapping of the interface states showed inhomogeneous contrasts with the lateral spatial scale of several hundreds of nanometers, suggesting that the physical origin of the trap states at SiO2/SiC interfaces is likely to be microscopically clustered.

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