Characterization and properties of Zn–O–Se ternary system thin films deposited by radio-frequency (rf)-magnetron sputtering

Zn–O–Se alloy films were grown on quartz substrate by radio-frequency (rf)-magnetron sputtering ZnSe single crystal target, with high pure Ar and O2 as working gas. X-ray diffraction and transmission electron microscopy characterizations indicate that the films are amorphous state. Energy disperse spectroscopy and X-ray photoelectron spectroscopy measurements verify the amorphous Zn–O–Se alloy was Se doped ZnO2 (Zn1−xSexO2), in which both Zn and Se atoms are bound with O atom. Absorption spectra exhibit that the optical band gap of Zn1−xSexO2 films are 4–5 eV. After annealing at 673 K in Ar ambient for 15 min, Zn1−xSexO2 film was decomposed to ZnO and SeO2, and SeO2 sublimed while annealed. The band gap energy decreased to the 3.2 eV, which is similar to the value of ZnO film directly deposited on quartz substrate. Room-temperature photoluminescence spectrum of the film after annealed shows NBE emission at 3.26 eV.