Defect distribution in ZnO thin films grown on a-plane sapphire substrates by catalytic-reaction-assisted chemical vapor deposition

This work examined the crystalline structure of a ZnO thin film grown on an a-plane sapphire substrate through a reaction between dimethylzinc and high-energy H2O molecules produced by the Pt-catalysed reaction of gaseous H2 and O2. The dislocation distribution in a ZnO film with a thickness of 5 mu m grown on an a-plane sapphire substrate was observed using cross-sectional dual-beam transmission electron microscopy, and the dislocation density was evaluated by Ham's method. A much higher dislocation density was found at the film-substrate interface than at the film surface. The influences of film thickness on the full width at half maximum of the X-ray diffraction rocking curve and on the electron mobility are both attributed to this localized high density of defects.

Automated summary

This study analyzed the crystalline structure and dislocation distribution of a ZnO thin film grown on an a-plane sapphire substrate. It was found that the film-substrate interface had a higher dislocation density than the film surface, leading to influences on the X-ray diffraction rocking curve and electron mobility.