The structure and vibrational modes of H-CAspairs in passivated AlAs grown by chemical beam epitaxy

AlAs layers grown by chemical beam epitaxy (CBE) and doped with either 12 C or 13 C have been passivated with hydrogen or deuterium. Infrared absorption lines due to hydrogen stretch modes, symmetric A 1 , modes and 'carbon-like' E modes of H-C As and D-C As pairs have been assigned for both carbon isotopes. Comparisons have been made with previous measurements made on H-C As centres in GaAs:C and with simple harmonic models, and the results are shown to be in agreement with ab initio local density functional calculations.