Effect of growth temperature on the properties of ZnO thin films prepared by laser molecular beam epitaxy

C-axis highly oriented ZnO thin films were prepared on C-plane sapphire substrates by laser molecular beam epitaxy(L-MBE) at the growth temperatures of 250°C;,300°C,350°C,400°C and 450°C. X-ray diffraction(XRD), photoluminescence(PL) spectra were used to analyze the crystalline and optical properties of the films. All measurement results show that the crystalline and optical properties of the films are improved with increase of growth temperature at lower temperature, and decrease when the growth temperature is above 350°C. This phenomenon indicates that there is a growth temperature range in the process of ZnO thin films growth by L-MBE. The reason for this phenomenon is also discussed.