CdZnTe substrate producibility and its impact on IRFPA yield

Sen, Sanghamitra; Hettich, H. L.; Rhiger, David R.; Price, Stephen L.; Currie, M. C.; Ginn, Robert; McLean, E. O.

doi:10.1007/s11664-999-0060-8

Cited by 11 publications

(2 citation statements)

References 3 publications

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“…The energy required for generating one electron-hole pair in CZT (;5 eV) is much less than that required for scintillation crystals coupled to photomultiplier tubes (;50 eV), resulting in better energy resolution. [6][7][8][9] (Received October 17, 2005; accepted December 14,2005) Although tremendous efforts have been made to grow large, high-quality CZT crystals, the production of CZT, dominated by the high-pressure Bridgman method, suffers from low yields and small device sizes. 5 Due to these advantages, CZT has been the material of choice for x-and g-ray detectors for medical imaging, infrared focal plane array, national security, environmental monitoring, and space astronomy.…”

Section: Introductionmentioning

confidence: 99%

Simulation, modeling, and crystal growth of Cd0.9Zn0.1Te for nuclear spectrometers

Mandal

Kang

Choi

et al. 2006

Journal of Elec Materi

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High-quality, large (10 cm long and 2.5 cm diameter), nuclear spectrometer grade Cd 0.9 Zn 0.1 Te (CZT) single crystals have been grown by a controlled vertical Bridgman technique using in-house zone refined precursor materials (Cd, Zn, and Te). A state-of-the-art computer model, multizone adaptive scheme for transport and phase-change processes (MASTRAP), is used to model heat and mass transfer in the Bridgman growth system and to predict the stress distribution in the as-grown CZT crystal and optimize the thermal profile. The model accounts for heat transfer in the multiphase system, convection in the melt, and interface dynamics. The grown semi-insulating (SI) CZT crystals have demonstrated promising results for high-resolution roomtemperature radiation detectors due to their high dark resistivity (r % 2.8 3 10 11 V cm), good charge-transport properties [electron and hole mobility-lifetime product, mt e % (2-5) 3 10 ÿ 3 and mt h % (3-5) 3 10 ÿ 5 respectively, and low cost of production. Spectroscopic ellipsometry and optical transmission measurements were carried out on the grown CZT crystals using two-modulator generalized ellipsometry (2-MGE). The refractive index n and extinction coefficient k were determined by mathematically eliminating the ;3-nm surface roughness layer. Nuclear detection measurements on the single-element CZT detectors with 241 Am and 137 Cs clearly detected 59.6 and 662 keV energies with energy resolution (FWHM) of 2.4 keV (4.0%) and 9.2 keV (1.4%), respectively.

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Section: Introductionmentioning

confidence: 99%

Simulation, modeling, and crystal growth of Cd0.9Zn0.1Te for nuclear spectrometers

Mandal

Kang

Choi

et al. 2006

Journal of Elec Materi

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“…͓DOI: 10.1063/1.2712496͔ Cd 0.9 Zn 0.1 Te ͑CZT͒ materials have widespread applications in gamma-ray detectors, infrared focal plane arrays, environmental monitoring, high energy astrophysics, and medical imaging devices. [1][2][3][4][5] This is due to several interesting properties of these materials including large absorption coefficient, low bias voltage requirement, and room temperature operation. In spite of the excellent promise shown by these materials, the material quality has not been fully optimized.…”

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confidence: 99%

Investigation of CdZnTe crystal defects using scanning probe microscopy

Koley

Liu

Mandal

2007

Applied Physics Letters

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Surface electronic properties of Cd0.9Zn0.1Te (CZT) crystals have been characterized using scanning spreading resistance microscopy (SSRM) and correlated with IR transmittance maps. SSRM performed on CZT samples showed excellent correlation with Te precipitates determined from infrared images. The average probe current was observed to be more than two orders of magnitude higher for the sample with higher Te precipitates. Stationary probe current-voltage relationship was found to be exponential and was modeled based on thermionic emission theory. Based on this model, the surface barriers of the CZT samples were found to be significantly different, which was confirmed independently from Kelvin probe measurements.

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