Thermally induced carbon–oxygen complexes in GaAs

In LEC‐grown oxygen‐containing GaAs, a vibrational absorption line is observed at 2059.6 cm –1 for T = 7 K after long‐time annealing at (700 ± 100) °C. This line is due to the stretching mode of a 12 C– 16 O complex, since the line due to the isotopically shifted 13 C– 16 O mode is observed at 2003.8 cm –1 . Several other 12 C– 16 O stretching modes found in this frequency region are assigned to C–O complexes with different environments. The formation of C–O complexes around 700 °C becomes possible as a result of the mobility of oxygen atoms. After the same annealing procedure, two vibrational lines are measured at 1828.2 and 1891.4 cm –1 for T = 7 K and assigned to the stretching modes of an 11 B– 16 O ( 10 B– 16 O) complex. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)