Publications
1.
Mandal, Krishna C.; Kang, Sung Hoon; Choi, Michael; Wei, Jiuan; Zheng, Lili; Zhang, Hui; Jellison, Gerald E.; Groza, Michael; Burger, Arnold
Component Overpressure Growth and Characterization of High-Resistivity CdTe Crystals for Radiation Detectors Journal Article
In: Journal of Electronic Materials, vol. 36, pp. 1013-1020, 2007.
@article{Mandal2007b,
title = {Component Overpressure Growth and Characterization of High-Resistivity CdTe Crystals for Radiation Detectors},
author = {Krishna C. Mandal and Sung Hoon Kang and Michael Choi and Jiuan Wei and Lili Zheng and Hui Zhang and Gerald E. Jellison and Michael Groza and Arnold Burger },
url = {http://link.springer.com/article/10.1007%2Fs11664-007-0164-y},
year = {2007},
date = {2007-07-06},
journal = {Journal of Electronic Materials},
volume = {36},
pages = {1013-1020},
abstract = {Spectrometer-grade CdTe single crystals with resistivities higher than 109 Ω cm have been grown by the modified Bridgman method using zone-refined precursor materials (Cd and Te) under a Cd overpressure. The grown CdTe crystals had good charge-transport properties (μτ e = 2 × 10−3 cm2 V−1, μτ h = 8 × 10−5 cm2 V−1) and significantly reduced Te precipitates compared with crystals grown without Cd overpressure. The crystal growth conditions for the Bridgman system were optimized by computer modeling and simulation, using modified MASTRAPP program, and applied to crystal diameters of 14 mm (0.55′′), 38 mm (1.5′′), and 76 mm (3′′). Details of the CdTe crystal growth operation, structural, electrical, and optical characterization measurements, detector fabrication, and testing using 241Am (60 keV) and 137Cs (662 keV) sources are presented.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Spectrometer-grade CdTe single crystals with resistivities higher than 109 Ω cm have been grown by the modified Bridgman method using zone-refined precursor materials (Cd and Te) under a Cd overpressure. The grown CdTe crystals had good charge-transport properties (μτ e = 2 × 10−3 cm2 V−1, μτ h = 8 × 10−5 cm2 V−1) and significantly reduced Te precipitates compared with crystals grown without Cd overpressure. The crystal growth conditions for the Bridgman system were optimized by computer modeling and simulation, using modified MASTRAPP program, and applied to crystal diameters of 14 mm (0.55′′), 38 mm (1.5′′), and 76 mm (3′′). Details of the CdTe crystal growth operation, structural, electrical, and optical characterization measurements, detector fabrication, and testing using 241Am (60 keV) and 137Cs (662 keV) sources are presented.
2.
Mandal, Krishna C.; Kang, Sung Hoon; Choi, Michael; Bello, Job; Zheng, Lili; Zhang, Hui; Groza, Michael; Roy, Utpal N.; Burger, Arnold; Jellison, Gerald E.; Holcomb, David E.; Wright, Gomez W.; Williams, Joseph A.
Simulation, modeling, and crystal growth of Cd0.9Zn0.1Te for nuclear spectrometers Journal Article
In: Journal of Electronic Materials, vol. 35, pp. 1251-1256, 2006.
@article{Mandal2006,
title = {Simulation, modeling, and crystal growth of Cd0.9Zn0.1Te for nuclear spectrometers},
author = {Krishna C. Mandal and Sung Hoon Kang and Michael Choi and Job Bello and Lili Zheng and Hui Zhang and Michael Groza and Utpal N. Roy and Arnold Burger and Gerald E. Jellison and David E. Holcomb and Gomez W. Wright and Joseph A. Williams },
url = {http://link.springer.com/article/10.1007%2Fs11664-006-0250-6},
year = {2006},
date = {2006-06-01},
journal = {Journal of Electronic Materials},
volume = {35},
pages = {1251-1256},
abstract = {High-quality, large (10 cm long and 2.5 cm diameter), nuclear spectrometer grade Cd0.9Zn0.1Te (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 room-temperature radiation detectors due to their high dark resistivity (ρ≈2.8 × 1011 Θ cm), good charge-transport properties [electron and hole mobility-life-time product, μτe≈(2–5)×10−3 and μτh≈(3–5)×10−5 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 241Am and 137Cs 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.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
High-quality, large (10 cm long and 2.5 cm diameter), nuclear spectrometer grade Cd0.9Zn0.1Te (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 room-temperature radiation detectors due to their high dark resistivity (ρ≈2.8 × 1011 Θ cm), good charge-transport properties [electron and hole mobility-life-time product, μτe≈(2–5)×10−3 and μτh≈(3–5)×10−5 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 241Am and 137Cs 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.
Note: Send e-mail to Prof. Kang at [email protected] if you need a pdf file of the papers below.
2007
Mandal, Krishna C.; Kang, Sung Hoon; Choi, Michael; Wei, Jiuan; Zheng, Lili; Zhang, Hui; Jellison, Gerald E.; Groza, Michael; Burger, Arnold
Component Overpressure Growth and Characterization of High-Resistivity CdTe Crystals for Radiation Detectors Journal Article
In: Journal of Electronic Materials, vol. 36, pp. 1013-1020, 2007.
Abstract | Links | BibTeX | Tags: CdTe, Characterization, Crystal, Detector, Growth
@article{Mandal2007b,
title = {Component Overpressure Growth and Characterization of High-Resistivity CdTe Crystals for Radiation Detectors},
author = {Krishna C. Mandal and Sung Hoon Kang and Michael Choi and Jiuan Wei and Lili Zheng and Hui Zhang and Gerald E. Jellison and Michael Groza and Arnold Burger },
url = {http://link.springer.com/article/10.1007%2Fs11664-007-0164-y},
year = {2007},
date = {2007-07-06},
journal = {Journal of Electronic Materials},
volume = {36},
pages = {1013-1020},
abstract = {Spectrometer-grade CdTe single crystals with resistivities higher than 109 Ω cm have been grown by the modified Bridgman method using zone-refined precursor materials (Cd and Te) under a Cd overpressure. The grown CdTe crystals had good charge-transport properties (μτ e = 2 × 10−3 cm2 V−1, μτ h = 8 × 10−5 cm2 V−1) and significantly reduced Te precipitates compared with crystals grown without Cd overpressure. The crystal growth conditions for the Bridgman system were optimized by computer modeling and simulation, using modified MASTRAPP program, and applied to crystal diameters of 14 mm (0.55′′), 38 mm (1.5′′), and 76 mm (3′′). Details of the CdTe crystal growth operation, structural, electrical, and optical characterization measurements, detector fabrication, and testing using 241Am (60 keV) and 137Cs (662 keV) sources are presented.},
keywords = {CdTe, Characterization, Crystal, Detector, Growth},
pubstate = {published},
tppubtype = {article}
}
Spectrometer-grade CdTe single crystals with resistivities higher than 109 Ω cm have been grown by the modified Bridgman method using zone-refined precursor materials (Cd and Te) under a Cd overpressure. The grown CdTe crystals had good charge-transport properties (μτ e = 2 × 10−3 cm2 V−1, μτ h = 8 × 10−5 cm2 V−1) and significantly reduced Te precipitates compared with crystals grown without Cd overpressure. The crystal growth conditions for the Bridgman system were optimized by computer modeling and simulation, using modified MASTRAPP program, and applied to crystal diameters of 14 mm (0.55′′), 38 mm (1.5′′), and 76 mm (3′′). Details of the CdTe crystal growth operation, structural, electrical, and optical characterization measurements, detector fabrication, and testing using 241Am (60 keV) and 137Cs (662 keV) sources are presented.
2006
Mandal, Krishna C.; Kang, Sung Hoon; Choi, Michael; Bello, Job; Zheng, Lili; Zhang, Hui; Groza, Michael; Roy, Utpal N.; Burger, Arnold; Jellison, Gerald E.; Holcomb, David E.; Wright, Gomez W.; Williams, Joseph A.
Simulation, modeling, and crystal growth of Cd0.9Zn0.1Te for nuclear spectrometers Journal Article
In: Journal of Electronic Materials, vol. 35, pp. 1251-1256, 2006.
Abstract | Links | BibTeX | Tags: Crystal, CZT, Growth, Modeling, Simulation, spectrometer
@article{Mandal2006,
title = {Simulation, modeling, and crystal growth of Cd0.9Zn0.1Te for nuclear spectrometers},
author = {Krishna C. Mandal and Sung Hoon Kang and Michael Choi and Job Bello and Lili Zheng and Hui Zhang and Michael Groza and Utpal N. Roy and Arnold Burger and Gerald E. Jellison and David E. Holcomb and Gomez W. Wright and Joseph A. Williams },
url = {http://link.springer.com/article/10.1007%2Fs11664-006-0250-6},
year = {2006},
date = {2006-06-01},
journal = {Journal of Electronic Materials},
volume = {35},
pages = {1251-1256},
abstract = {High-quality, large (10 cm long and 2.5 cm diameter), nuclear spectrometer grade Cd0.9Zn0.1Te (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 room-temperature radiation detectors due to their high dark resistivity (ρ≈2.8 × 1011 Θ cm), good charge-transport properties [electron and hole mobility-life-time product, μτe≈(2–5)×10−3 and μτh≈(3–5)×10−5 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 241Am and 137Cs 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.},
keywords = {Crystal, CZT, Growth, Modeling, Simulation, spectrometer},
pubstate = {published},
tppubtype = {article}
}
High-quality, large (10 cm long and 2.5 cm diameter), nuclear spectrometer grade Cd0.9Zn0.1Te (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 room-temperature radiation detectors due to their high dark resistivity (ρ≈2.8 × 1011 Θ cm), good charge-transport properties [electron and hole mobility-life-time product, μτe≈(2–5)×10−3 and μτh≈(3–5)×10−5 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 241Am and 137Cs 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.