Simulation study of neutron radiation damage to cadmium zinc telluride

Abstract

In recent years, the development of new semiconductor materials has made an opportunity and challenge for technological innovation and the development of emerging industries. Among them, cadmium zinc telluride materials have highlighted important application prospects due to their excellent properties. The CdZnTe, as the third-generation cutting-edge strategic semiconductor material, has the advantages of high detection efficiency, low dark current, strong portability, and applicability at room temperature without additional cooling system. However, when the cadmium zinc telluride detector is exposed to radiation environment for a long time, it will cause different degrees of radiation damage, which will affect the performance of the device or even fail to work, and greatly shorten the service time of the detector in the radiation field. The transport process of 1.00–14.00 MeV neutrons in CdZnTe material is simulated to obtain the information about the primary knock-on atoms, and then by combining with the cascade collision model, the irradiation of neutrons with different energy in CdZnTe material is analyzed. The damage is simulated and calculated. The calculation results are shown below. The energy of most of the primary knock-on atoms is located at the low-energy end, and with the increase of the incident neutron energy, the types of primary knock-on atoms are more abundant, and the energy also increases gradually. With neutron irradiation of CdZnTe, the non-ionizing energy loss is uniformly distributed along the depth direction in the material, and the non-ionizing energy loss first increases and then decreases with the increase of the incident neutron energy. The calculation results of displacements per atom(dpa) show that the dpa also increases first with the increase of the incident neutron energy. And further analysis shows that the number of Te displacement atom atoms and the number of the Zn displacement atoms both increase first and decrease then with the increase of incident neutron energy, while the number of Cd displacement atoms increases with the increase of incident neutron energy, which is co-modulated by its inelastic scattering cross-section and other nuclear-like reaction cross-sections. The comprehensive analysis shows that with the increase of the incident neutron energy, inelastic scattering becomes the main factor causing the internal displacement damage of the material.