Simulation, Modeling, and Crystal Growth of Cd_0.9Zn_0.1Te for Nuclear Spectrometers

Journal Article · Sun Jan 01 00:00:00 EST 2006 · Journal of Electronic Materials

DOI:https://doi.org/10.1007/s11664-006-0250-6· OSTI ID:1003604

Mandal, Krishna ^[1]; Kang, Sung Hoon ^[1]; Choi, Michael ^[1]; Bello, Job ^[1]; Zheng, Lili ^[2]; Zhang, Hui ^[2]; Groza, Michael ^[3]; Roy, Utpal N. ^[3]; Burger, Arnold ^[3]; Jellison, Jr, Gerald Earle ^[4]; Holcomb, David Eugene ^[4]; Wright, Gomez W ^[4]; Williams, Joseph A ^[4]

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1. EIC Laboratories, Inc.
2. State University of New York, Stony Brook
3. Fisk University, Nashville, TN
4. ORNL

High-quality, large (10 cm long and 2.5 cm diameter), nuclear spectrometer grade Cd{sub 0.9}Zn{sub 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 room-temperature radiation detectors due to their high dark resistivity ({rho} {approx} 2.8 x 10{sup 11} {Theta} cm), good charge-transport properties, electron and hole mobility-life-time product, {mu}{tau}{sub e} {approx} (2-5) x 10{sup -3} and {mu}{tau}{sub h} {approx} (3-5) x 10{sup -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 {approx}3-nm surface roughness layer. Nuclear detection measurements on the single-element CZT detectors with {sup 241}Am and {sup 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.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1003604
• Journal Information: Journal of Electronic Materials, Vol. 35, Issue 6; ISSN 0361--5235
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CHARGE TRANSPORT
COMPUTERS
CONVECTION
CRYSTAL GROWTH
DETECTION
ELECTRONS
ELLIPSOMETRY
ENERGY RESOLUTION
HEAT TRANSFER
MASS TRANSFER
MONOCRYSTALS
PRECURSOR
RADIATION DETECTORS
REFRACTIVE INDEX
ROUGHNESS
SPECTROMETERS
TRANSPORT