Improved electrical properties of detector-grade Cd[formula omitted] single crystals passivated by KMnO4 and K2S2O8 solutions.

Surface treatment is very important for detector-grade Cd 1−x Zn x Te crystals. In this paper, electrical properties of detector-grade Cd 1−x Zn x Te single crystals passivated by KMnO 4 and K 2 S 2 O 8 solutions were investigated. Four passivation agents, H 2 O 2 , (NH 4) 2 S, KMnO 4 and K 2 S 2 O 8 , were compared. The results indicated that the leakage current decreased obviously after passivation. It was found that KMnO 4 and K 2 S 2 O 8 had better passivation effect. When the passivation time was 1 min and 2 min, KMnO 4 had the best passivation effect, and the leakage current of Cd 1−x Zn x Te crystal was as low as 1.3 nA. However, when the passivation time was 5 min, the passivation effect of K 2 S 2 O 8 was the best, and the leakage current was as low as 0.7 nA. The chemical reactions of KMnO 4 and K 2 S 2 O 8 with Cd 1−x Zn x Te crystals were proposed due to XPS analysis. PL spectra showed that the surface properties of the Cd 1−x Zn x Te crystals changed obviously after passivation. 241Am γ -ray @59.5 keV energy resolution of the detectors fabricated with the crystals passivated by KMnO 4 and K 2 S 2 O 8 solutions for 5 min were notably improved. In particular, the energy resolution of Cd 1−x Zn x Te planar detector with K 2 S 2 O 8 passivation could reach 8.03% and was improved by 236%. • Surface treatment is very important for room temperature detectors. • Electrical properties of passivated detector-grade Cd 1−x Zn x Te single crystals were investigated. • Four passivation agents, H 2 O 2 , (NH 4) 2 S, KMnO 4 and K 2 S 2 O 8 , were compared. • The leakage current decreased obviously after passivation. • Energy resolution of the detectors passivated by KMnO 4 and K 2 S 2 O 8 solutions were notably improved. [ABSTRACT FROM AUTHOR]