Changes in optical and electrical properties and surface recombination velocity of n-type GaN due to (NH4)2Sx treatment

We have employed the photoluminescence (PL), surface photovoltage spectroscopy (SPS) and Hall effect measurements to study the effects of (NH4)2Sx treatment on the optical and electrical properties of n-type GaN (n-GaN) in this study. (NH4)2Sx treatment of n-GaN led to the decrease of the surface recombination velocity and the increase of the band-edge emission intensity, due to the accumulation of majority carriers and the repulsion of minority carriers near the (NH4)2Sx-treated n-GaN surface, the removal of the native oxide existed on the n-GaN, and sulfur passivation.