Hexagonal BN epitaxial growth on (0 0 0 1) sapphire substrate by MOVPE

Hexagonal boron nitride (h-BN) epitaxial films were successfully grown on (0 0 0 1) sapphire substrate by metalorganic vapor phase epitaxy (MOVPE). BN films were grown using triethylboron and ammonia (NH3) at various V/III ratios ranging from 210 to 2100. BN films grown at high V/III ratios above 1280 showed two X-ray diffraction (XRD) peaks, one from the (0 0 0 2) plane and the other from the (0 0 0 4) plane of h-BN, and exhibited a clear peak at 1366 cm−1 of the first h-BN Raman mode as well. In contrast, XRD revealed that structures in BN films grown at low V/III ratios below 640 were turbostratic. These results indicate that the structure of the BN film grown on sapphire substrate by MOVPE strongly depends on the V/III ratio and that the BN growth under a high V/III ratio could lead to the growth of (0 0 0 1) h-BN epitaxial films on (0 0 0 1) sapphire substrates.