Investigation on the two-step passivation process for CdZnTe detectors

In this paper, the composition, morphology and electrical properties of the passivation layer for CdZnTe detectors were investigated. A two-step passivation was performed under different conditions, including passivation time, temperature and NH₄F/H₂O₂ concentration. The obtained passivation layers were characterized by XRD, SEM, XRF and I-V methods. The results showed that the best passivation condition was with the NH₄F/H₂O₂ concentration of 10wt%, passivation time of 40min and temperature of 20ºC. Under this condition, the passivation layer was purely oxidized and compact, and the surface leakage current of CZT crystals was most effectively reduced.