Pulsed sputtering epitaxial growth of m-plane InGaN lattice-matched to ZnO

Abstract

m-Plane GaN and InGaN films were grown on m-plane ZnO substrates at ~350 °C by pulsed sputtering deposition. It was found that the critical thickness of the m-plane GaN films grown on ZnO lies between 25 and 62 nm, whereas 180-nm-thick m-plane In0.12Ga0.88N can be coherently grown on ZnO substrates, which is explained well by theoretical calculations based on an energy-balance model. The coherently grown m-plane InGaN on ZnO exhibited narrow X-ray rocking curves compared with the m-plane GaN grown on ZnO. These results demonstrate the benefit of lattice-matched ZnO substrates for epitaxy of high-quality nonpolar InGaN films.