The comprehensive evaluation of the structural and functional properties of the gas- statically treated Au–CdZnTe–Au structures for X- and gamma-ray detectors

Abstract The influence of the gas-static processing on the optical, structural and electrophysical properties of Au–CdZnTe–Au structures, used in X- and gamma-ray detectors, was investigated. The processing, which is described in detail in the experimental part, was done in a laboratory-scale setup “GAUS-4/2000-35” with the following process parameters: pressure=0.32±0.02 GPa, temperature ~170 °C, time=2 h. The influence of the mentioned processing on the photoluminescence, the Raman scattering, the electric resistance, the I–V characteristics and the spectrometric parameters of the Au–CdZnTe–Au structures was determined. The physical mechanisms, through which the gas-static processing induces changes in the structural and functional properties, were analyzed. It was observed that the gas-static processing (with the above-mentioned process parameters) of the Au–CdZnTe–Au structures leads to a significant increase of the electric resistance of the structures; it also leads to the increase of the intensity of the photoelectric absorption peak when the respective detector is registering X- and gamma-radiation with energy near 32.19 keV. The Raman and photoluminescence data indicates the formation of the surface oxides TeO x and the compensation of Cd vacancies by Au atoms. The assumption that, under the discussed processing, two different rival processes modify the Au–CdZnTe junction due to the influence of the increased temperature ~170 °C and pressure ~0.3 GPa, was suggested. The first process is the formation of TeO 2 oxide (which increases the electric resistance) on the contact; the second process is the destruction of the surface films of the oxides and the absorbed gases. Most likely, the first process is dominant, which was evidenced by the Raman and photoluminescence measurements.