CZT SINGLE CRYSTALS FOR GAMMA RADIATION DETECTORS AND IMAGING APPLICATIONS

Cadmium zinc telluride (Cd0.9Zn0.1Te) is a highly promising semiconductor for gamma-ray spectroscopy due to its superior energy resolution, compactness, and stable room-temperature operation. These advantages make it an excellent alternatives to scintillators, silicon (Si), and high-purity germanium (HPGe) detectors. This chapter describes the development of infrastructure for growing detector-grade CdZnTe single crystals using a custom-designed Traveling Heater Method (THM) crystal growth system equipped with a multi-zone furnace. A series of systematic experiments was conducted to optimize critical growth parameters, including growth temperature, temperature gradient, growth rate, and the solvent (Te) to solute (CdZnTe) ratio, in order to obtain high-quality crystals. The grown crystals were comprehensively characterized for their structural, electrical, and optical properties using X-ray diffraction, electrical resistivity measurements, near-infrared/mid-infrared (NIR/Mid-IR) transmission, photoluminescence spectroscopy, and Infrared (IR) Transmission microscopy. Post-growth processing conditions were further optimized to produce detector-grade crystal elements. These efforts culminated in the fabrication of a portable gamma radiation spectrometer, assembled using the in-house-grown CdZnTe detectors and commercially available electronic components. Finally, the potential of these detectors for industrial gamma imaging applications was demonstrated through their integration into a Computed Tomography (CT) system.