Impurity incorporation in semipolar (1-1 0 1) GaN grown on an Si substrate

Abstract

Carbon doping was investigated in (1-1 0 1) GaN, where the topmost surface is terminated by nitrogen. Intentional doping was performed supplying C2H2 as the source precursor during the MOVPE growth under N2 ambient. The sample showing p-type conduction exhibited a strong but broad peak at 361 nm in a low-temperature cathode luminescence spectrum. FTIR analyses were performed on these samples and a new absorption peak at 945 cm−1 was found along with an AlN–A1(LO) phonon mode at 888 cm−1. SIMS analyses showed unintentionally highly doped Al in the sample. The 945 cm−1 peak was assigned to a local vibration mode related to an Al–C bond.