Ga14N/Ga15N/Ga14N isotope heterostructures were used to study nitrogen self-diffusion by secondary-ion mass spectrometry and thermally activated decomposition. After interdiffusion of Ga14N and Ga15N layers at between 770 and 970C the diffusion profiles were measured. The temperature dependence of the nitrogen self-diffusion coefficient in hexagonal GaN was described by:

D(cm2/s) = 1600 exp [-4.1eV/kT]

leading to a self-diffusion entropy of about 10k.

O.Ambacher, F.Freudenberg, R.Dimitrov, H.Angerer, M.Stutzmann:  Japanese Journal of Applied Physics – 1, 1998, 37[5], 2416-21