Structural and Optical Properties of ZnO Films with Different Thicknesses Grown on Sapphire by MOCVD

【Abstract】 ZnO（002） films with different thicknesses, grown on Al₂O₃（006） substrates by metal-organic chemical vapor deposition（MOCVD）, were etched by Ar ion beams. The samples were examined by D8 X-ray diffraction, scanning electron microscopy（SEM）, and photoluminescence（PL） spectrometry. The structural properties vary with the increasing thickness of the films. When the film thickness is thin, the phi（Ф） scanning curves for ZnO（103） and sapphire（116） substrate show the existence of two kinds of orientation relationships between ZnO films and sapphire, which are ZnO（002）//Al₂O₃（006）, ZnO（100）//Al₂O₃（110） and ZnO（002）//Al₂O₃（006）, ZnO（110）//Al₂O₃（110）. When the thickness increases to 500 nm there is only one orientation relationship, which is ZnO（002）//Al₂O₃（006）, ZnO [100]//Al₂O₃[110]. Their photoluminescence（PL） spectra at room temperature show that the optical properties of ZnO films have been greatly improved when increasing the thickness of films is increased.更多还原