Complexes of group-VI donors with hydrogen in GaP

Local vibrational modes due to complexes of hydrogen with sulfur, selenium and tellurium in gallium phosphide are reported together with the corresponding mode due to the deuterium-sulfur complex. The wave numbers of these modes indicate that hydrogen or deuterium binds to one of the host phosphorus atoms which are next-nearest neighbors of the group-VI donor. Experiments under uniaxial stress show that the complexes have C-s (C-1h) symmetry, the mirror planes being {110} planes. The orientation of the mode-induced electric dipole moment is determined for each of the complexes. The structure of the complexes of group-VI donors with hydrogen in GaP is different from the one determined previously in other III-V compounds such as GaAs or AlSb. (C) 1999 Elsevier Science B.V. All rights reserved.