Simulation of CdTe:Ge crystal properties for nuclear radiation detectors

We report on the simulation results of the electrical properties of a coplanar detector made from Ge-doped CdTe crystals. The simulations have been performed using the commercial modeling package MEDICI. The detailed models of material behavior have been created by varying the concentration of three standard traps associated with CdTe:Ge crystals. These traps are the A-center related to Cd vacancy-residual impurity complex, the Te vacancy defect and the Ge impurity. Their energetic positions were measured by photoluminescence technique. The simulation has revealed the effects of the traps on several important detector characteristics such as leakage current and electric field distribution.