Properties of semiconductor scintillator ZnSe:O

Zinc selenide (ZnSe:O) single crystals doped with 2 wt% of oxygen were grown by Bridgman–Stockbarger technique and annealed under excess Zn conditions. The lattice constants of the ZnSe single crystals were obtained from X-ray diffractometer (XRD) data. It is found that, after annealing at 1290 K under excess Zn conditions, the lattice constant decreases but it increases with oxygen impurity. From the absorption spectra, the band gap energies of the ZnSe single crystals were calculated by a linear fitting process. Under excess Zn conditions, the band gap energy of the ZnSe:O single crystals decreases from 2.60 to 2.58 eV with annealing but that of ZnSe single crystals does not change. The maximum emission wavelength of the radioluminescence of the annealed ZnSe:O scintillator excited by X-rays was 595 nm. The afterglow level of the annealed ZnSe:O scintillator after 5 ms was 0.012%. The relative light output of the annealed ZnSe:O was 1.277 times higher than for CsI:Tl. The energy resolution of the annealed ZnSe:O scintillator in a size of 10×10×1 mm3 was 7.4%, when it was exposed to 137Cs γ-ray. The annealed ZnSe:O scintillator can detect charged particles and low-energy γ rays.