Given a bandgap in UV (5.9 eV), the sp 2 -hybridized forms of boron nitride (sp 2 -BN) , hexagonal BN (h-BN) and rhombohedral BN (r-BN) are promising thin film materials for application in UV-optoelectronics. As for the other 13-15 semiconductor materials AlN, GaN, and InN, chemical vapor deposition (CVD) is a suitable thin film synthesis route for sp -BN. However, deposition of crystalline sp 2 -BN films by thermal CVD often requires deposition temperatures above 1200 °C. This limits the choice of substrate materials for epitaxy seen from demonstrated growth on 3C-SiC(111), 4H-and 6H-SiC(0001) and Al2O3(0001).