Electroreflectance of hexagonal gallium nitride at the fundamental and E1 spectral regions

Abstract

We have measured the room-temperature electroreflectance (ER) of hexagonal gallium nitride. Our measurements were obtained at the fundamental optical gap and at the E1 critical point regions. The measurements were performed using front contact ER. In the fundamental region, the ER spectra were found to be of excitonic nature and in the low field regime. In the E1 region, the ER spectra were also in the low field regime, but were fitted with two-dimensional critical points.