Molecular Beam Epitaxy Growth of Single-Domain and High-Quality ZnO Layers on Nitrided (0001) Sapphire Surface

Nitridation of a (0001) sapphire substrate was used to eliminate the rotation domains and improve the quality of a ZnO film grown by rf-plasma-assisted molecular beam epitaxy. It was found that a very thin nitrogen polar AlN layer, which was formed by nitridation, acted as a template for the following growth of the ZnO film, resulting in the elimination of the rotation domains which were often observed in the case without nitridation. The full width at half maximum of (002) and (102) X-ray diffraction ω-scans decreased from 912 and 2870 arcsec to 95 and 445 arcsec, respectively, due to the effect of sapphire nitridation. Based on this, its optical quality was also improved.