Substrate Misorientation Effect On Cubic And Hexagonal GaN Grown On GaAs By Molecular Beam Epitaxy Using RF-radical Nitrogen Source

GaN is one of the basic materials for blue and ultraviolet light emission devices. Usually, GaN has a hexagonal (wurtzite) structure, but recently, the successhl growth of cubic (zincblende) GaN was obtained on various cubic crystal substrates, such as G~A.S~)-~), psi@), Si7) etc. Especially, with gas-source molecular beam epitaxy using a RF-radical nitrogen source, the initial surface nitridation effects of GaAs substrates on the GaN crystal structure was reported31, where when without surface nitridation, cubic GaN were obtained, but on hlly nitrided GaAs substrates, hexagonal GaN were grown. In this talk, the substrate misorientation effect on cubic and hexagonal GaN grown on intentionally misoriented GaAs by the same GSMBE as the above was investigated. As increasing the substrate misorientation angle (SMA) from (100) surface toward the [Oll] direction, the blue-shift of photoluminescence (PL) peak was observed for GaN grown on GaAs substrates without nitridation, and no PL peak shift was observed for the fidly nitridation case. On (100) exact GaAs, the PL peak wavelengths of cubic and hexagonal GaN were 380nm and 360nm, respectively. Here the growth mechanism will be discussed characterizing grown GaN crystals.