Development of CdTe nuclear radiation detectors for spectroscopy and imaging applications

CdTe nuclear radiation detectors were developed for spectroscopy and imaging applications. Detectors were fabricated in two different techniques in order to alleviate the poor hole charge transport property in CdTe semiconductor. The first type comprises an M-π-n diode type detector fabricated by growing an n-type CdTe epitaxial layer on the p-like high resistivity CdTe crystal wafer. This detector is operated in a reverse bias mode, which allows us to apply high electric field on the detector without increasing the leakage current noise of the detector. The second type is a multi-electrode pixel type detector working on a small pixel effect. It has three electrodes in each pixel on one side and a common cathode on the opposite side. Performance of both types of detectors will be presented.