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. •Annealing P-type layer at high temperature and in the presence of NH3 significantly changes hydrogen concentration.•Annealing N-type layer at high temperature and in the presence of NH3 does not changes hydrogen concentration.•The amount of substrate dislocation has no significant effect on the diffusion of hydrogen.•The changes of hydrogen content induced changes in blue and yellow luminescence.