CARBON-HYDROGEN COMPLEXES IN VAPOR-PHASE EPITAXIAL GAN

Carbon-hydrogen complexes in undoped and Mg-doped epitaxial GaN films have been investigated using Fourier transform infrared spectroscopy. Infrared absorption peaks in the Mg-doped material were observed at 28 53, 2923, and 2956 cm(-1). The absorption peaks are attributed to the symmetric and asymmetric vibrational stretching modes of C-H in CHn (n =1-3) defect complexes. The carbon-hydrogen complexes were unintention ally incorporated during the Mg-doped GaN film growth. The absorbances of the vibrational modes increased for heavily Mg-doped GaN. Upon ann ealing at 700 degrees C for 30 min under nitrogen environment, the com plexes decomposed. The origin of the carbon-hydrogen complexes is disc ussed. (C) 1997 American Institute of Physics.