In liquid-encapsulated Czochralski-grown O-containing material, a vibrational absorption line was observed at 2059.6/cm at 7K, following long-term annealing at 600 to 800C. This line was attributed to the stretching mode of a 12C-16O complex, since the line due to the isotopically shifted 13C-16O mode was observed at 2003.8/cm. Several other 12C-16O stretching modes, found in this frequency range, were attributed to C-O complexes with differing environments. The formation of C-O complexes at around 700C became possible as a result of the mobility of the O atoms. Following a given annealing procedure, two vibrational lines were measured at 1828.2 and 1891.4/cm, at 7K, and were attributed to the stretching modes of an 11B-16O (10B-16O) complex.

Thermally Induced Carbon-Oxygen Complexes in GaAs. W.Ulrici, M.Jurisch: Physica Status Solidi B, 2005, 242[12], 2433-9