The analysis of X-ray response of CdZnTe detectors

CdZnTe is an excellent material candidate for high efficiency, high-resolution room-temperature nuclear radiation detectors, and the CdZnTe detectors are being widely used in medicine, industry, safeguard and scientific X-ray and γ-ray imaging and spectroscopic applications. In this work, three CdZnTe planar detectors with different grades, named CZT-1, CZT-2 and CZT-3, respectively, were fabricated. And the effects of mobility, lifetime and de-trapping time on the performance of CdZnTe planar detector, such as the energy resolution, charge collection efficiency and peak to valley ratio, were analyzed. The charge collection efficiency depends on the product of carrier mobility and lifetime, which has a great effect on the energy resolution of detector when the efficiency is less than 90%. The de-trapping time of carriers in deep levels should be responsible for the peak to valley ratio and "polarization".