Investigation of neutron irradiation effects on the properties of Au/CdZnTe junction

The metal/semiconductor interface plays an important role in semiconductor detectors for high energy radiation, such as that in CdZnTe detectors. Nevertheless, very little attention has been paid to radiation damage effects on the metal/semiconductor interface, especially the Schottky barrier interface. The influence of 2 MeV neutron irradiation on current-voltage (I–V) and direct current photoconductivity properties of Au/CdZnTe/Au structure with a Schottky barrier on the interface as a function of neutron fluences are investigated. The irradiation fluences were 1 × 10¹⁰ and 1 × 10¹¹ neutron/cm², respectively. The current transport across the Au/CdZnTe junction is described by the diffusion process. Several mechanisms for the effects such as Pool-Frankel effect, surface recombination and electron tunnelling are suggested, which may account for the variations of I–V curves and photoconductivity properties of CdZnTe detectors after irradiation. Various interface Schottky barrier parameters, such as Schottky barrier height and the donor concentration, have been discussed as a function of neutron irradiation fluences. The observed variation of Au/CdZnTe interface states are mainly attributed to the defects and electron active traps induced by the neutron irradiation.