It was found that GaN epilayers which were grown, via molecular beam epitaxy, by cracking NH3 on the growing surface, contained H. Depending upon the H concentration, GaN on (00•1) sapphire could be under either biaxially compressive strain or biaxially tensile strain. The use of X-ray photo-electron spectroscopy of the N 1s region indicated that the H was bound to N. it was concluded that the micro-defect, Ga...H-N, was effectively a N vacancy in this nitride.

Electrical Properties of GaN Deposited onto Nitrided Sapphire by Molecular Beam Epitaxy using NH3 Cracked on the Growing Surface. J.P.Zhang, D.Z.Sun, X.B.Li, X.L.Wang, M.Y.Kong, Y.P.Zeng, J.M.Li, L.Y.Lin: Journal of Crystal Growth, 1999, 201-202, 429-32