Reduction of Leakage Currents in CdZnTe-Based X-ray and γ-ray Detectors: a II-VI Semiconductor Superlattice Approach

An approach to the fabrication of CdZnTe-based heterojunction detectors is presented with the primary goal of reducing leakage currents, permitting increased bias voltages and therefore improving x-ray and gamma-ray detector performance. The p-i-n detector architecture is theoretically superior to traditional CdZnTe detectors, and our modeling predicts that superlattice contact layers result in leakage current reductions relative to bulk semiconductor contacts. The benefits arise because the superlattices can be designed to have large carrier effective masses along the electric field direction yet a density of states less than that of a comparable bulk semiconductor.