Influence of hydrogenation on surface morphologies, transport, and optical properties of InN epifilms

We report the investigation of surface morphologies and transport and optical properties of hydrogenated InN epifilms. The average rms surface roughness decreases from 24 nm on the as-grown sample to 13.2 nm after hydrogenation. The free electron concentration can be increased or decreased depending on the duration of hydrogenation. The linewidth of the photoluminescence spectra can be reduced, and the peak intensity can be enhanced by about three times. All our results indicate that the physical properties of InN films can be improved by hydrogenation. Possible origins of the underlying mechanism have been proposed to explain the improvement.