Exfoliation of AlN film using two-dimensional multilayer hexagonal BN for deep-ultraviolet light-emitting diodes

Crack-free crystalline AlN film was synthesized on two-dimensional multilayer hexagonal BN (h-BN) by metal organic vapor phase epitaxy (MOVPE). The multilayer h-BN was directly grown on sapphire substrates in wafer scale by MOVPE, with a thickness of 2.9 nm. The AlN film grown on the h-BN/sapphire presented a smooth surface. We further realized the exfoliation of AlN film utilizing the weak bonds within h-BN layers. Moreover, the AlGaN-based deep-ultraviolet light-emitting diodes grown on the AlN/h-BN/sapphire template exhibited obvious emissions at 281 nm. It is promising that the multilayer h-BN will pave the way to obtain transferable high-efficiency devices with wafer scale.