Hydrogen diffusion in GaN:Mg and GaN:Si

Theoretical predictions of high hydrogen diffusivity in p-GaN layers were confirmed in many experiments for samples grown by Metalorganic Vapor Phase Epitaxy (MOVPE). In this technology, p-GaN has a high concentration of hydrogen incorporated during the growth. In this work, we confirm that also in hydrogen-free p-GaN grown by Plasma Assisted Molecular Beam Epitaxy (PAMBE) the hydrogen diffusion during H2+NH3 annealing is much higher than in n-type layers. Additionally, we have compared hydrogen diffusion for samples of different dislocation density and we have found no effect of these defects. The photoluminescence of the PAMBE-grown p-GaN exhibited the following change after annealing in H2+NH3 atmosphere: the blue luminescence decrease and yellow luminescence increase.