THE STRUCTURE AND VIBRATIONAL-MODES OF H-C(AS) PAIRS IN PASSIVATED ALAS GROWN BY CHEMICAL BEAM EPITAXY

AlAs layers grown by chemical beam epitaxy (CBE) and doped with either C-12 or C-13 have been passivated with hydrogen or deuterium. Infrared absorption lines due to hydrogen stretch modes, symmetric A1 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.