2 LOCAL VIBRATIONAL-MODES RELATED TO HYDROGEN IN GAN

We have observed two absorption bands located at around 1730 and 2960 cm(-1) in the infrared (IR) absorption spectra from undoped GaN sample s which are grown using low pressure metalorganic vapor phase epitaxy and irradiated by gamma ray and then exposed to a radio frequency hydr ogen plasma. Proton implantation followed by gamma-ray irradiation of the GaN samples can also activate the IR band at around 1730 cm(-1). B ased on the experimental results, we tentatively ascribe the 1730 cm(- 1) band to the local vibrational modes of Ga-H complexes in the vicini ty of N vacancies and the 2960 cm(-1) band to those of either N-H comp lexes in the vicinity of Ga vacancies or C-H complexes. (C) 1997 Ameri can Institute of Physics.