Secondary ion mass spectroscopy investigations of magnesium and carbon doped gallium nitride films grown by molecular beam epitaxy

The incorporation of magnesium and carbon in GaN grown by molecular beam epitaxy (MBE) has been investigated by secondary ion mass spectroscopy (SIMS) and other techniques. We have grown Mg:GaN in a wide range of chemical concentrations 1 x 10(17)-1 x 10(19) cm(-3). Low temperature photoluminescence of Mg:GaN is dominated by the donor-acceptor transitions associated with Mg at similar to 3.253 eV. Carrier concentration for Mg:GaN in the range 1 x 10(17)-2 x 10(18) cm(-3) with mobilities <10 cm(2) V-1 s(-1) were measured by the Hall effect technique. In the C:GaN layers, it was found that carbon can be uniformly incorporated into the layer at a concentration similar to 2 x 10(10) dm(-3). However, at this high concentration there is a tendency for carbon to diffuse into the undoped GaN buffer layer.