The effect of hydrogenation was investigated by using hetero-epitaxial layers that had been grown by means of metalorganic chemical vapor deposition. The layers were of Mg-doped p-type after thermal activation, or were of Si-doped n-type. Elemental depth profiles which were obtained by means of secondary ion mass spectroscopy revealed a striking contrast after deuteration at 600C. That is, the D concentration in Mg-doped material was approximately equal to 1019/cm3, whereas there was no detectable D in the n-type material. Variable-temperature Hall-effect measurements provided the most direct evidence so far for Mg-H complex formation; with the decrease in hole concentration upon hydrogenation being accompanied by an increase in the hole Hall mobility.

W.Götz, N.M.Johnson, J.Walker, D.P.Bour, H.Amano, I.Akasaki: Applied Physics Letters, 1995, 67[18], 2666-8