Growth of ZnSe single crystals from Zn–Se–Zn(NH 4) 3Cl 5 system

Abstract

A modified chemical vapor transport method in a closed-tube system was developed to grow ZnSe single crystals from zinc–selenium –Zn(NH 4) 3Cl 5 system, where Zn(NH 4) 3Cl 5 served as the chemical transport agent to avoid the kinetics limitations of the congruent sublimation conditions to ZnSe crystals growth. The growth temperature of 1001–1005 °C was employed. The ZnSe crystal with a dominated (1 1 1) singular face was obtained. The structure characteristic and crystalline quality of as-grown ZnSe single crystal were investigated by several methods such as XRD, rotating orientation X-ray diffraction, double-crystal diffraction, photoluminescence spectrum and optical microscope. The infrared transmission spectra and ultraviolet absorption measurement of as-grown crystal were also reported. The microscopic observation on the surface of as-grown ZnSe crystal revealed that two-dimension dendrite crystal growth governs the crystal growth in the system. Comparing this result with the growth of ZnSe–Zn(NH 4) 3Cl 5 system suggested that ZnSe single-crystal grown directly from two elements in one step has lower purity and quality than ZnSe crystal grown from ZnSe polycrystal source system.