Study of deep levels in high resistivity CdZnTe by discharge current measurement

Abstract

We studied polarization in high-resistivity CdZnTe with resistivity ∼ 108Ωcm using Au as a contact metal. After application of voltage on the samples with Schottky contacts we employed the Pockels electrooptic effect. We observed that the electric field in the sample without irradiation decreases from the cathode forming a dead layer below the anode. This situation corresponds to a positive space charge accumulated in the sample due to band bending upwards at the Au/CdZnTe interface. We performed measurements of time and temperature dependence of discharge current to determine energy levels responsible for accumulation of space charge. We have observed that energy levels responsible for polarization in samples contacted with Au contacts (bands bent upwards) are in the range of 0.4-0.7eV. © 2012 IOP Publishing Ltd and Sissa Medialab srl.