Recent CdZnTe detector fabrication developments

High resistivity CdZnTe has attracted extensive interests for its use as x-ray and gamma-ray detector operated at room and elevated temperature due to its superior electro-optical and structural properties compared to other materials. The post- growth surface annealing under constituent over pressure, passivation, oxidation and chemical etching in terms of restoring stoichiometry, reducing surface damage and charge carrier trapping centers have been investigated by low temperature photoluminescence, x-ray photoelectron spectroscopy and atomic force microcopy. The choice of contacting metal and deposition method also plays an important role in lowering surface leakage current and increasing the ohmic behavior between contact and detector, and subsequently directly affects the detector performance. The data revealed by spectroscopic and microscopic measurements were correlated with current-voltage and x-ray spectrum results to give an improved detector fabrication process based on CdZnTe detector. These results are presented and discussed.