Structure and Dynamics of the Be-H Complex in GaAs.

The symmetry and reorientation kinetics of the Be-H complex in GaAs have been determined in a uniaxial stress study. The splitting of the 2036 cm sup (-1) vibrational absorption band under stress shows that the complex has trigonal symmetry. The size of the splitting is large and is consistent with a bond-centered position for the H similar to B-H in Si. At temperatures near 120 K the complex can be aligned by an applied stress. A study of the annealing kinetics of the alignment shows that the motion of H from bond-centered site to bond-centered site about the Be acceptor is thermally activated with an energy of 0.37 eV.