Hydrogen passivation of deep levels in n-GaN

Differential postgrowth hydrogen passivation of deep levels in n-GaN grown by metal-organic chemical vapor deposition has been directly observed by means of both deep level transient spectroscopy and deep level optical spectroscopy. Two deep levels found at E-c-E-t = 0.62 and 1.35 eV show strong H passivation effects, with their concentrations decreasing by a factor of greater than or equal to 30 and similar to 14, respectively. The decrease in the 0.62 eV trap concentration together with its correlation with the presence of Mg in n-GaN is consistent with Mg-H complex formation. A band of closely spaced deep levels observed at E-c-E-t=2.64-2.80 eV narrows to E-c-E-t = 2.74-2.80 eV after hydrogenation, consistent with hydrogen complexing with V-Ga(3-) defects as anticipated by earlier theoretical results. Finally, a deep level at E-c-E-t = 3.22 eV likely related to background acceptors remains unaffected by hydrogen. (C) 2000 American Institute of Physics. [S0003-6951(00)01635-1].