Hydrogen in-situ etching of GaN surface to reduce non-radiative recombination centers in 510-nm GaInN/GaN quantum-wells

Abstract

This study aims to improve the internal quantum efficiency (IQE) of GaInN/GaN 510-nm green quantum-wells (QWs) by reducing the surface defects (SDs) at the n-type GaN surface using in-situ etching. For this purpose, we examined hydrogen (H2) and a mixture of H2 and ammonia (NH3) as the etching gases for surface etching of n-type GaN at various reactor temperatures and pressures. The results show that the in-situ etching performed effectively for the SD reduction, while the surface morphology of n-type GaN slightly deteriorated. Next, we examined the effect of in-situ etching on the IQE of QWs via the growth of 510-nm GaInN/GaN QWs on the surface-etched n-type GaN. The results show that the IQE at 300 K improved by a factor of 2.1 through the H2 + NH3 etching and 3.0 through the H2 etching, which is attributable to the fact that the SDs were more sufficiently removed using H2 as an etching gas, despite the slightly undesired shape of QW because they were grown on the roughed n-type GaN surface. Meanwhile, some SDs remained when H2 + NH3 was used as an etching gas.