Effect of growth temperature on the properties of ZnO thin films prepared by L-MBE

Highly oriented ZnO thin films were prepared on C-plane sapphire substrates by laser molecular beam epitaxy (L-MBE) at the growth temperature of 250,300,350,400 and 450°C. X ray diffraction, photoluminescence spectra and reflection high energy electron diffraction were employed to analyze the crystalline and optical properties of the films. All the measurement results show that the crystalline and optical properties of the films are improved with the rise of growth temperature, whereas deteriorated with growth temperature above 350°C. This phenomenon indicates that there is a adaptable growth temperature range in the process of ZnO thin films grown by L-MBE. The mechanism of this phenomenon is also discussed.