An investigation was made of p-type GaN:Mg materials using noise spectroscopy. The epitaxial Mg-doped GaN layers were grown onto a sapphire substrate by metalorganic chemical vapour deposition. Significant generation–recombination noise was observed and shown to be linked to metastable DX-like centres. These centres were correlated with metastable defects having optical ionization energies of 1.1 and 1.9eV, respectively; as previously reported. The energy barriers for capture into, and emission from, the fundamental state were quantitatively determined. A model was proposed, for the configuration coordinate diagram, that explained the persistent photoconductivity in GaN:Mg in the light of the results obtained by noise spectroscopy.

Noise and its Correlation to Deep Defects in Mg-Doped GaN. D.Seghier, H.P.Gislason: Journal of Physics D, 2005, 38[6], 843-6