Published online by Cambridge University Press: 21 February 2011
We report on methods for the growth of GaN by MBE directly on 6H-SiC substrates. The films were doped p-type by the incorporation of Mg and the samples were characterized by studying their structure and morphology by RHEED, XRD and SEM and their recombination properties by photoluminescence measurements. The undoped films were found to be atomically smooth with 2×2 surface reconstruction and have an x-ray rocking curve with a FWHM of 3.5 arcmin. The photoluminescence spectra indicate that recombination is dominated by transition across the gap. The p-type doped films have a rocking curve with FWHM of 6.5 arcmin. and the majority of recombination occurs through D-A transitions at 3.26 eV.