Synthesis and Optical Characterization of Oxygen-Incorporated ZnS(1-x)Ox for UV-Visible Color Palette Light-Emission Matter

Abstract

Single crystals of oxygen-incorporated ZnS (i.e., ZnS(1-x)Ox series) are environment-friendly wide-band-gap semiconductors available for light-emitting devices and solar cell use. The series of materials has considerable potential for use in visible ultraviolet areas with flexibility for palette emissions. In this study, we grow oxygen-incorporated ZnS series crystals by chemical vapor transport method with iodine (I2) as the transport agent. Three different oxygen-incorporated crystals of undoped ZnS, ZnS0.94O0.06, and ZnS0.88O0.12 are studied. Through structural studies, ZnS doped with oxygen crystallizes in the main sphalerite phase and a little wurtzite structure. The lattice constants of the major cubic phase are determined to be a = 5.43 Å (ZnS), 5.41 Å (ZnS0.94O0.06), and 5.39 Å (ZnS0.88O0.12). Three band-edge excitonic transitions are simultaneously detected by thermoreflectance measurement for the ZnS, ZnS0.94O0.06, and ZnS0.88O0.12 series samples. The energy positions of the band-edge transitions decrease as the oxygen content increases in the ZnS(1-x)Ox series. Defect-state and surface-state emissions, including sulfur vacancy, oxygen vacancy, zinc interstitial, and so forth, can emit approximately full-color spectra from the near band edge of the ZnS(1-x)Ox series crystals. With adjusting the oxygen content, the ZnS(1-x)Ox can be a series of color-palette luminescence matters that applied for fluorescent display or light-emitting device.