Structure and dynamics of carbon, silicon, and hydrogen complexes in AlAs, GaAs, and Al_xGa_1-xAs

The results of a comprehensive Green’s-function calculation are reported for the structure and dynamics of the amphoteric behavior of silicon {Si_Ga(Al),Si_As}, and the acceptor nature of beryllium and carbon {Be_Ga(Al),C_As} impurities in GaAs, AlAs, and Al_xGa_1-xAs. Impurity vibrational modes are studied for (i) the nearest-neighbor C_As-Al_Ga pairs (C_2v symmetry) in Al_xGa_1-xAs (for x<0.04), (ii) the second-nearest-neighbor {e.g., C_As-Al(Ga)-C_As; Si_Al-As-Be_Al} pairs (C_2v /C_s symmetry) in AlAs (GaAs), and (iii) the passivated H-C_As complexes in GaAs and AlAs. Comparisons are made with the existing experimental and theoretical data.