The influences of annealing temperature on the structure and optical properties of ZnS:Mn/GaN multilayer thin films

Abstract

The influences of annealing temperature on the structure, morphology and optical properties of ZnS:Mn/GaN multilayer thin films have been investigated. X-ray diffraction (XRD) results show that the ZnS:Mn thin films have a cubic structure which is oriented along β-ZnS (1 1 1) plane. With the increase of annealing temperature, the diffraction peak intensity of the films increases, and the surface morphology becomes dense and rough, along with the increase of the crystalline grain size. Ultraviolet and visible spectrophotometer results show that the average transmittance of the ZnS:Mn film can reach 85% in the visible light range when it is annealed at 500 °C. Room temperature photoluminescence (PL) measurements show that ZnS:Mn/GaN multilayer thin films have two luminescence bands at about 440 nm and 595 nm after annealing. The relative integrated intensity ratio of the blue light (440 nm) to the orange-red light (595 nm) can be regulated by the annealing temperature, and the obtained light is close to white light. This make ZnS:Mn/GaN multilayer thin films have a potential application in white light emitting devices.