Microstructure and optical properties of ZnAlO films prepared by Magnetron sputtering

ZnAlO thin films with different Al concentrations were prepared on glass and silicon substrates by Magnetron sputtering in this paper. Scanning electron microscopy (SEM), X-ray diffraction (XRD), spectrometer and other instruments were used to analyze the surface morphology, microstructure, transmittance and Raman spectrum of the films. The results showed that trace Al doping significantly increased the surface morphology and size of ZnAlO thin films; The low doped ZnAlO thin film exhibits a good preferred orientation. As the Al doping concentration increases, the main growth direction of the crystal gradually shifts from (101) to (103), and the grain size decreases with the increase of doping concentration during low doping; When the wavelength of ZnAlO film is less than 330 nm, the transmittance of the film is almost zero; When the wavelength is greater than 350 nm, the transmittance of the thin film decreases with the increase of Al doping concentration, and there is a blue shift trend with the increase of Al concentration. When the wavelength is between 420-900nm, the average transmittance of ZnAlO thin film can reach over 90%, and the transmission performance is good; The ZnAlO thin films all have structural characteristic peaks of wurtzite with a frequency of about 437 cm-1, and the Raman peak position does not move with the increase of Al concentration.