MOVPE growth of semipolar AlN on m-plane sapphire

Abstract: We report on the growth of semipolar AlN by metal-organic vapor phase epitaxy on sapphire. High temperature nitridation and nucleation at a V/III ratio of 1050 provide single phase AlN with mirror like crack free surfaces, even for layer thicknesses larger than . Increasing reactor pressure results in lower growth rates because of gas phase particle formation. The in-plane relationship is and and therewith similar to MBE grown AlN and MOVPE and HVPE grown GaN on m-plane sapphire. The AlN reflex is anisotropically broadened in XRD. The surface shows an undulation along as typical for oriented nitride epilayers. Transmission spectroscopy measurements exhibit a sharp absorption edge at 5.95eV, which is 130meV shifted towards lower energies compared to c-plane AlN. [Copyright &y& Elsevier]