Modified compensation model of CdTe

Fiederle, M.; Eiche, C.; Salk, M.; Schwarz, R.; Benz, K.W.; Stadler, Wolfgang; Hofmann, D. M.; Meyer, B. K.

doi:10.1063/1.368874

Cited by 199 publications

(103 citation statements)

References 24 publications

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“…The compensation between the deep-level Te antisites, the Cd interstitials, and the Cd vacancies is considered responsible for the high resistivity of CZT. 6,7 This compensation could be lost due to extra Cd interstitials introduced during annealing in Cd vapor, thereby shifting the Fermi level toward the bottom of the conduction band or the top of the valence band. Furthermore, we measured the lowtemperature PL spectrum of as-grown and annealed CZT (Fig.…”

Section: Resultsmentioning

confidence: 99%

Post-growth Annealing of Cadmium Zinc Telluride Crystals for Room-Temperature Radiation Detectors

Yang

Bolotnikov

Fochuk

et al. 2012

Journal of Elec Materi

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We investigated the effects of post-growth annealing on cadmium zinc telluride crystals intended for use as room-temperature radiation detectors. Annealing under Cd vapor effectively eliminated Te inclusions. The material's resistivity was lowered, and loss of Zn component was observed. Annealing under Cd + Zn vapors similarly removed Te inclusions. Furthermore, after exposure to the two vapors, we noted a change in the crystal surface morphology, i.e., formation of patterns of parallel lines. In contrast to annealing under Cd vapor alone, high resistivity was maintained after suitably controlling the Cd and Zn pressures.

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Section: Resultsmentioning

confidence: 99%

Post-growth Annealing of Cadmium Zinc Telluride Crystals for Room-Temperature Radiation Detectors

Yang

Bolotnikov

Fochuk

et al. 2012

Journal of Elec Materi

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“…CdTe:Bi doped crystals were grown by the vertical Bridgman method using different dopant concentrations from 10 17 -10 19 at./ cm 3 . Samples of 10ϫ 10ϫ 1.5 mm 3 were cut, and then mechanically and chemically polished as was previously reported.…”

Section: Methodsmentioning

confidence: 99%

“…1,2 Deep levels play a key role on the electrical and transport charge properties of CdTe, determining the final detector's performance. [3][4][5][6] For example, has been demonstrated that the presence of these recombination deep centers is the mainly reason of the polarization effect of detectors, leading to the collapse of their internal electric field. The mechanism has been interpreted by the accumulation of charges in these recombination centers.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the origin of deep levels in CdTe doped with Bi

Saucedo

Franc

Elhadidy

et al. 2008

Journal of Applied Physics

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Combining optical ͑low temperature photoluminescence͒, electrical ͑thermoelectric effect spectroscopy͒, and structural ͑synchrotron X-ray powder diffraction͒ methods, the defect structure of CdTe doped with Bi was studied in crystals with dopant concentration in the range of 10 17 -10 19 at./ cm 3 . The semi-insulating state observed in crystals with low Bi concentration is assigned to the formation of a shallow donor level and a deep donor recombination center. Studying the evolution of lattice parameter with temperature, we postulate that the deep center is formed by a Te-Te dimer and their formation is explained by a tetrahedral to octahedral distortion, due to the introduction of Bi in the CdTe lattice. We also shows that this model agrees with the electrical, optical, and transport charge properties of the samples.

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“…Undoped GaTe is p-type with low resistivity ͑20 ⍀ ·cm͒ and low mobility ͑15 cm 2 / V·s͒. 2 To meet radiation detector application requirements ͑resistivityϾ 1 ϫ 10 9 ⍀ · cm, mobilityϳ 1 ϫ 10 3 cm 2 / V·s͒, the material should possess deep levels near the middle of the band gap, 13 and dopants have to be introduced into the material to compensate the native shallow acceptors. The type and intensity of both intrinsic and extrinsic defects have influence on the fundamental properties of GaTe; it is important to study defect levels between the valence and the conduction bands of GaTe crystals.…”

Section: Introductionmentioning

confidence: 99%

Deep levels in GaTe and GaTe:In crystals investigated by deep-level transient spectroscopy and photoluminescence

Cui

Caudel

Bhattacharya

et al. 2009

Journal of Applied Physics

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Deep levels of undoped GaTe and indium-doped GaTe crystals are reported for samples grown by the vertical Bridgman technique. Schottky diodes of GaTe and GaTe:In have been fabricated and characterized using current-voltage, capacitance-voltage, and deep-level transient spectroscopy ͑DLTS͒. Three deep levels at 0.40, 0.59, and 0.67 eV above the valence band were found in undoped GaTe crystals. The level at 0.40 eV is associated with the complex consisting of gallium vacancy and gallium interstitial ͑V Ga -Ga i ͒, the level at 0.59 eV is identified as the tellurium-on-gallium antisite ͑Te Ga ͒, and the last one is tentatively assigned to be the doubly ionized gallium vacancy ͑V Ga ‫ء‬ ͒. Indium isoelectronic doping is found to have noticeable impacts on reducing the Schottky saturation current and suppressing the densities of Te Ga and V Ga ‫ء‬ defects. The peak which dominated the DLTS spectrum of GaTe:In is assigned to be the defect complex consisting of V Ga and indium interstitial ͑In i ͒. Low-temperature photoluminescence ͑PL͒ spectroscopy measurements were performed on GaTe and GaTe:In crystals. A shallow acceptor level at 140 meV corresponding to V Ga was measured in undoped GaTe. Two shallow acceptor levels at 123 and 74 meV corresponding to V Ga and indium-on-gallium antisite In Ga were observed in GaTe:In samples. The PL results suggested that the indium atoms could occupy gallium vacant sites during GaTe crystal growth period and thereby change the electrical and optical properties of GaTe crystal.

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Modified compensation model of CdTe

Cited by 199 publications

References 24 publications

Post-growth Annealing of Cadmium Zinc Telluride Crystals for Room-Temperature Radiation Detectors

Post-growth Annealing of Cadmium Zinc Telluride Crystals for Room-Temperature Radiation Detectors

Investigation of the origin of deep levels in CdTe doped with Bi

Deep levels in GaTe and GaTe:In crystals investigated by deep-level transient spectroscopy and photoluminescence

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