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 2853, 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 unintentionally incorporated during the Mg-doped GaN film growth. The absorbances of the vibrational modes increased for heavily Mg-doped GaN. Upon annealing at 700 degrees C for 30 min under nitrogen environment, the complexes decomposed. The origin of the carbon-hydrogen complexes is discussed. (C) 1997 American Institute of Physics.