Properties of carbon as an acceptor in cubic GaN

Abstract Cubic gallium nitride epilayers were successfully doped with carbon using an e-beam evaporation source. Room temperature Hall measurements revealed hole concentrations up to 6×10 17  cm −3 and hole mobilities of 200 cm 2 /V s. Low temperature (2 K) photoluminescence showed a donor–acceptor transition at 3.08 eV, which could clearly be assigned to the incorporation of a carbon acceptor. Thermal activation measurements were performed. They exhibited an activation energy of E A =215 meV both in photoluminescence and electrical measurements, respectively.