HIGH-ENERGY X-RAY DIFFRACTION AND TOPOGRAPHY INVESTIGATION OF CDZNTE

摘要: High-energy transmission x-ray diffraction techniques have been applied to investigate the crystal quality of CdZnTe (CZT). has shown excellent performance in hard and gamma detection; unfortunately, bulk nonuniformities still limit spectroscopic properties CZT detectors. Collimated high-energy x-rays, produced by a superconducting wiggler at National Synchrotron Light Source’s X17B1 beamline, allow for nondestructive characterization thick samples (2–3 mm). In order complete information about defect distribution strains crystals, two series experiments performed. First, monochromatic 67 keV beam with size 300×300 µm2 was used measure rocking curves crystals supplied different material growers. A raster scan few square centimeter area allowed us full-width half-maximum (FWHM) shift peak position across crystal. The curve its FWHM can be correlated local stoichiometry variations other defects. Typically, values ranging from 8.3 arcsec 14.7 were measured best these measurements. Second, white topography (WBXT) performed using 22 mm×200 µm energy range 50 200 keV. These types measurements large area, high-resolution (50 µm) scans samples. Usually, this technique is visualize growth process-induced defects, such as dislocations, twins, domains, inclusions, etc. difference contrast shows parts that could not otherwise. topography, good indicative high sample, while blurred gray presence Correlation (e.g., infrared (IR) mapping mapping) also attempted. Our techniques, which use highly penetrating are valid in-situ measurements, even after electrical contacts formed on working device. Thus, studies may lead understanding effects defects device ultimately improving required fabrication. It important study ingot positions (bottom, center, top); consequently, more systematic involving center border planned.