Stabilization of bulk p-type and surface n-type carriers in Mg-doped InN {0001} films

The formation of p-type carriers in InN {0001} films by Mg doping is theoretically investigated by means of the highly precise thin film full-potential linearized augmented plane-wave method. The first-principles calculations simultaneously simulating both p-type and n-type carriers in the bulk and surface layers, respectively, demonstrate that the formation energies of a substitutional Mg atom in the surface region are lower than those in the bulk due to the compensation mechanism. The Mg is, however, stabilized in the bulk layers due to a large diffusion-barrier height, suggesting a possible mechanism for the stabilization of Mg in the bulk and the formation of p-type carriers.