CdTe:Cl and CdTeSe:Cl Single Crystals Application for Radiation Detectors

1993 ◽  
Vol 302 ◽  
Author(s):  
B.K. Meyer ◽  
D.M. Hofmann ◽  
W. Stadler ◽  
M. Salk ◽  
C. Eiche ◽  
...  
Keyword(s):  
Deep Level ◽  
Radiation Detector ◽  
Radiation Detectors ◽  
Electrical And Optical Properties ◽  
Shallow Acceptor ◽  
Deep Donor ◽  
Vertical Bridgman ◽  
Hall Effect Measurements ◽  
Resistive Material ◽  
Donor State

ABSTRACTWe report on electrical and optical properties of vertical Bridgman grown Cl-doped CdTe including the ternary compositions Cd0.9Zn0.1Te and CdTe0 9Se0.1 with respect to application as a radiation detector. Based on Hall effect measurements, photoinduced current spectroscopy (PICTS) and photoluminescence we infer that high resistive material with good performance is controlled by deep level defects. The resistivity is calculated as a function of the shallow acceptor concentration (Cl-A-centers) with the conclusion that a deep donor state at mid gap must be present.

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.

scholarly journals Deep level related yellow luminescence in p-type GaN grown by MBE on (0001) sapphire

2000 ◽  
Vol 5 (S1) ◽  
pp. 754-760
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

Yellow luminescence (YL) has been studied in GaN:Mg doped with Mg concentrations ranging from 1019 to 1021 cm-3 by spectral CL (T=K) 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.

A Study of Bismuth Induced Levels in CZT Using TEES/TSC

2009 ◽  
Vol 1164 ◽  
Author(s):  
Raji Soundararajan ◽  
Kelly A. Jones ◽  
Santosh Swain ◽  
Kelvin Lynn
Keyword(s):  
Cross Section ◽  
Ionization Energy ◽  
Radiation Detector ◽  
Radiation Detectors ◽  
Thermal Ionization ◽  
Thermo Electric ◽  
High Electrical Resistivity ◽  
Deep Donor ◽  
Defect Levels ◽  
Electric Effect

AbstractConsidering the desirable effects of doping CdTe with heavy elements like Bi, we have grown a Cadmium Zinc Telluride (Zn=10%) ingot with Bi (doping levels ∼1014 to 1015 at/cm3) as the heavy element dopant for use as a room temperature radiation detector, using the Bridgman method. In-spite of a high bulk resitivity (∼1010?cm), and the ability to hold high electric field (>2000 V/cm), these lightly doped crystals had a poor spectral resolution for the Co-57 photo peaks and ??e measurements were so low that these measurement were not reliable. Thermo electric effect spectroscopy (TEES) and thermally stimulated current (TSC) experiments on samples C and F (single crystals close to the tip and the heel of the ingot respectively) have revealed various defect levels in the band gap. Among these defect levels, we have identified and characterized two Bi-related deep levels namely a deep donor level L5 (thermal ionization energy: 0.33[5] to 0.39[5] eV and trap cross-section: 7.1[5] × 10-17 to 2.54 [5] × 10-16 cm2), and a deep acceptor level L8 (thermal ionization energy of 0.82 [5] eV and trap cross-section of 2.59 [5] × 10-12 cm2). These levels were responsible for the observed high electrical resistivity (∼1010 ?*cm) in the CdZnTe samples. From a comparison to studies on Bi doped CdTe samples, level L8 was tentatively associated with the (0/-) transition of (BiCd- - OTe) complex, however is still under study. Since these defect levels also act as trapping centers for charge carriers, in spite of the semi-insulating behavior the samples are poor radiation detectors.

scholarly journals Characteristics of TlBr single crystals grown using the vertical Bridgman-Stockbarger method for semiconductor-based radiation detector applications

2016 ◽  
Vol 34 (2) ◽  
pp. 297-301 ◽  
Author(s):  
Dong Jin Kim ◽  
Joon-Ho Oh ◽  
Han Soo Kim ◽  
Young Soo Kim ◽  
Manhee Jeong ◽  
...  
Keyword(s):  
Single Crystals ◽  
High Performance ◽  
Radiation Detector ◽  
Radiation Detectors ◽  
Middle Part ◽  
High Quality ◽  
Single Crystalline ◽  
Crystalline Sample ◽  
Vertical Bridgman ◽  
Stockbarger Method

AbstractTlBr single crystals grown using the vertical Bridgman-Stockbarger method were characterized for semiconductor based radiation detector applications. It has been shown that the vertical Bridgman-Stockbarger method is effective to grow high-quality single crystalline ingots of TlBr. The TlBr single crystalline sample, which was located 6 cm from the tip of the ingot, exhibited lower impurity concentration, higher crystalline quality, high enough bandgap (>2.7 eV), and higher resistivity (2.5 × 1011 Ω·cm) which enables using the fabricated samples from the middle part of the TlBr ingot for fabricating high performance semiconductor radiation detectors.

Defect Studies in n-Type GaN Grown by Molecular Beam Epitaxy

1995 ◽  
Vol 378 ◽  
Author(s):  
W. Götz ◽  
D. B. Oberman ◽  
J. S. Harris
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Electron Cyclotron Resonance ◽  
Deep Level ◽  
Growth Parameters ◽  
Ecr Plasma ◽  
Gas Source ◽  
Deep Donor ◽  
Hall Effect Measurements ◽  
Gas Source Mbe

AbstractGaN thin films grown by molecular beam epitaxy (MBE) were characterized by Hall effect measurements in the temperature range from 80 K to 500 K and by photoluminescence spectroscopy (PL) at 2 K and at 300 K. These films were grown by MBE utilizing either electron cyclotron resonance (ECR) plasma activated nitrogen gas or thermally cracked hydrogen azide (HN3) as the source of chemically reactive nitrogen. The electrical properties of the GaN films grown by ECR plasma assisted MBE were found to vary with growth parameters, dominated either by shallow donors with activation energies (ΔE)in the range between 10 meV and 30 meV or deep donor levels (ΔE; > 500 meV). GaN grown by (HN3) gas-source MBE exhibited metallic conduction and electron mobilities <1 cm2/Vs. However, these films displayed sharp photoluminescence lines at 3.360 eV and 3.298 eV and no deep level related luminescence, whereas only broad deep level related emission was observed in the PL spectra of the ECR plasma assisted MBE grown GaN films.

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.

Structural, electrical, and optical property studies of indium-doped Hg0.8Cd0.2Te/Cd0.96Zn0.04Te heterostructures

1999 ◽  
Vol 14 (7) ◽  
pp. 2778-2782 ◽  
Author(s):  
M. S. Han ◽  
T. W. Kang ◽  
T. W. Kim
Keyword(s):  
Hall Effect ◽  
Ftir Spectra ◽  
Epitaxial Layers ◽  
High Quality ◽  
Electrical And Optical Properties ◽  
Vacancy Defects ◽  
Transmission Electron ◽  
Hall Effect Measurements ◽  
Transmission Measurements ◽  
Van Der Pauw

Transmission electron microsopy (TEM), Hall effect, and Fourier transform infrared (FTIR) transmission measurements were performed to investigate the structural, electrical, and optical properties of indium-doped Hg0.8Cd0.2Te epitaxial layers grown on Cd0.96Zn0.04Te (211) B substrates by molecular-beam epitaxy. The TEM measurements showed that high-quality Hg0.8Cd0.2Te epitaxial layers with interfacial abruptnesses were grown on the Cd0.96Zn0.04Te substrates. The Van der Pauw Hall effect measurements on typical indium-doped Hg0.8Cd0.2Te/Cd0.96Zn0.04Te heterostructures with a doping concentration of 6 × 1016 cm−3 at 10 K in a magnetic field of 0.5 T yielded a carrier density and a mobility of 2.2 × 1016 cm−3 and 40,000 cm2/V s, respectively. The FTIR spectra showed that the absorption edges of the indium-doped Hg0.8Cd0.2Te/Cd0.96Zn0.04Te heterostructures shifted to a shorter wavelength range than those of the undoped samples, which was caused by the Burstein–Moss effect. The FTIR spectra also showed that the transmittance intensities of the indium-doped Hg0.8Cd0.2Te/Cd0.96Zn0.04Te heterostructures increased compared with those of the undoped heterostructures, which is due to the compensation of the Hg vacancy defects by the indium atoms. These results indicate that the indium-doped Hg0.8Cd0.2Te epitaxial layers were high-quality n-type layers and that p-HgxCd1−xTe epilayers can be grown on indium-doped Hg0.8Cd0.2Te/Cd0.96Zn0.04Te heterostructures for the fabrication of HgxCd1−xTe photoconductors and photodiodes.

Electrical and Optical Properties of Vanadium in Omvpe-Grown GaAs

1989 ◽  
Vol 145 ◽  
Author(s):  
W. S. Hobson ◽  
S. J. Pearton ◽  
V. Swaminathan ◽  
A. S. Jordan ◽  
Y. J. Kao ◽  
...  
Keyword(s):  
Deep Level ◽  
Vanadium Content ◽  
Epitaxial Layers ◽  
Electrical And Optical Properties ◽  
Vanadium Concentration ◽  
Co Doping ◽  
Undoped Material ◽  
Maximum Value ◽  
Si Doped ◽  
Transient Spectroscopy

AbstractThe electrical and photoluminescent properties of vanadium incorporated into GaAs epitaxial layers from a VO(OC2 H5)3 source during organometallic vapor phase epitaxy were examined. The vanadium concentration in the GaAs was controllably varied from 1016 to 1018 atoms cm−3. Deep level transient spectroscopy showed the presence of an electron trap at Ec – 0.15 eV which increased in concentration with vanadium content of the epitaxial layers. A maximum value of 8 × 1015 cm−3 for this trap was obtained. There were no midgap electron traps associated with vanadium. In intentionally Si-doped epitaxial layers, co-doping with vanadium was observed to have no effect in reducing the carrier density when the Si concentration was > 4 × 1016 cm−3. The net carrier concentration profiles resulting from 29 si implantation into GaAs containing 1018 cm−3of total V had sharper tails than for similar implantation into undoped material, indicating the presence of less than 1016 cm−3V-related acceptors. Photoluminescent spectra exhibited the characteristic V+3intracenter emission at 0.65∼0.75 eV. No other deep level photoluminescence was detected. For a V concentration of 1016 cm−3only 2.5 × 1013 cm−3was electrically active. Over the entire V concentration investigated this impurity was predominantly (≥99%) inactive.

scholarly journals Оптические сечения поглощения и силы осцилляторов двойного донора магния в кремнии

2021 ◽  
Vol 55 (4) ◽  
pp. 299
Author(s):  
Ю.А. Астров ◽  
Л.М. Порцель ◽  
В.Б. Шуман ◽  
А.Н. Лодыгин ◽  
Н.В. Абросимов ◽  
...  
Keyword(s):  
Cross Sections ◽  
Ionization Energy ◽  
Binding Energies ◽  
Oscillator Strengths ◽  
Group V ◽  
Deep Donor ◽  
Hall Effect Measurements ◽  
Substitutional Impurities ◽  
Electron Binding Energies ◽  
Intracenter Transitions

The optical properties of magnesium impurity in silicon, whose atoms at interstitial positions in the lattice are deep double donors with an ionization energy of 107.56 meV in the neutral state, were studied. For optical transitions from the ground state of a neutral center to the excited levels 2p0 and 2p, the absorption cross sections and oscillator strengths were determined. These parameters were calculated from the impurity absorption spectra that were measured at T  K in samples with different magnesium concentrations. The deep donor content in the samples was determined using Hall effect measurements in the temperature range 78–300 K. The obtained characteristics of intracenter transitions in magnesium were compared with the corresponding literature data for shallow Group V donors in silicon, which are substitutional impurities. It was found that the optical characteristics of the investigated transitions in magnesium are consistent with the dependences of the corresponding parameters on the ionization energy for shallow donors, extrapolated to the region of larger electron binding energies.

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