Higher voltage X- and γ-ray Schottky diode detectors with low leakage current

A significant improvement in CdTe X- and γ-ray detector performance has been achieved. This was accomplished by using semi-insulating CdTe single crystals and unified technology, where both Schottky and near-ohmic contacts were formed by the deposition of the same metal (Ni) on the opposite surfaces of the crystal pre-treated by chemical etching and Ar ion bombardment with different parameters. Reduction of injection of minority carriers from the near-ohmic contact in the neutral part of the diode and high Schottky barrier for holes provides low leakage current even at high bias voltage (≪ 50 nA/cm² at 2000 V and at room temperature). The current-voltage characteristics of the detectors with Ni/CdTe/Ni electrode configuration are described by the generation-recombination Sah-Noyce-Shockley theory excepting the high reverse voltage range where injection of minority carriers takes place.