17 September 2014 Characterization of high-resistivity CdTe and Cd0.9Zn0.1Te crystals grown by Bridgman method for radiation detector applications
Author Affiliations +
Abstract
CdTe and Cd0.9Zn0.1Te (CZT) crystals have been studied extensively for various applications including x- and γ-ray imaging and high energy radiation detectors. The crystals were grown from zone refined ultra-pure precursor materials using a vertical Bridgman furnace. The growth process has been monitored, controlled, and optimized by a computer simulation and modeling program developed in our laboratory. The grown crystals were thoroughly characterized after cutting wafers from the ingots and processed by chemo-mechanical polishing (CMP). The infrared (IR) transmission images of the post-treated CdTe and CZT crystals showed average Te inclusion size of ~10 μm for CdTe and ~8 μm for CZT crystal. The etch pit density was ≤ 5×104 cm-2 for CdTe and ≤ 3×104 cm-2 for CZT. Various planar and Frisch collar detectors were fabricated and evaluated. From the current-voltage measurements, the electrical resistivity was estimated to be ~ 1.5×1010 Ω-cm for CdTe and 2-5×1011 Ω-cm for CZT. The Hecht analysis of electron and hole mobility-lifetime products (μτe and μτh) showed μτe = 2×10-3 cm2/V (μτh = 8×10-5 cm2/V) and 3-6×10-3 cm2/V (μτh = 4- 6×10-5 cm2/V) for CdTe and CZT, respectively. Detectors in single pixel, Frisch collar, and coplanar grid geometries were fabricated. Detectors in Frisch grid and guard-ring configuration were found to exhibit energy resolution of 1.4% and 2.6 %, respectively, for 662 keV gamma rays. Assessments of the detector performance have been carried out also using 241Am (60 keV) showing energy resolution of 4.2% FWHM.
© (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Krishna C. Mandal, Krishna C. Mandal, Ramesh M. Krishna, Ramesh M. Krishna, Rahmi O. Pak, Rahmi O. Pak, Mohammad A. Mannan, Mohammad A. Mannan, } "Characterization of high-resistivity CdTe and Cd0.9Zn0.1Te crystals grown by Bridgman method for radiation detector applications", Proc. SPIE 9213, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics XVI, 92131L (17 September 2014); doi: 10.1117/12.2063054; https://doi.org/10.1117/12.2063054
PROCEEDINGS
9 PAGES


SHARE
Back to Top