Polycrystalline CdZnTe Thick Films for Low Energy X-ray: System Evaluation

Abstract

The X-ray response of polycrystalline-CdZnTe was measured by signal-to-noise (S/N) analysis. The CdZnTe material has optimal properties in a solid-state X-ray detector, and much research has focused on single crystal CdZnTe with a small-sized, silicon readout device. However, it would be difficult to apply CdTe or CdZnTe single crystal to large area, flat panel detectors, such as those used for radiography and mammography. As an alternative of single crystal CdZnTe, we have grown thick, polycrystalline CdZnTe films of high resistivity (>5 x 10(9) Ohm cm) using the thermal evaporation method on carbon substrate. A high signal-to-noise value has a direct impact on the performance of CdZnTe X-ray detectors. Important image parameters, such as dynamic range and detective quantum efficiency, rely on the signal and noise characteristics of the system. In this paper, we analyzed the properties of the X-ray detector and obtained images of the X-ray detector using the data acquisition system. The X-ray detector used the Cd1-xZnxTe (x=0.04), which used carbon substrate and gold as the electrode. The detector design is planar and 32 mm x 10 mm in size, and it has a 1.75mm x 1mm pixel electrode size and a detector thickness of 150 microm.

The surface morphology, structural properties and chemical composition of Cd1−xZnxTe polycrystalline thick films deposited by close spaced vacuum sublimation

“…Despite the fact that polycrystalline materials contain more structural defects than single crystals, the polycrystalline thick CZT films are also used as a detector material [6][7][8][9]. It is due to ability to produce low-cost, large-area flat panel detectors [8,10] based on thick films free of Te-inclusions with zinc concentration x > 0.10 and uniform zinc distribution [11]. At the same time application in electronic devices, especially fabrication of radiation detectors, requires high-quality CZT films with big grain size, high texture, low concentration of defects, and uniform distribution of chemical elements.…”