The defects which were produced by H implantation at 80K were investigated. After implantation, a predominant absorption band at 2029/cm, for As-H centers, was observed. A 10/cm full-width at half-maximum of the band at 80K, and a marked dependence of the frequency and bandwidth upon temperature, revealed the bonding of H at displacement defects within the lattice. The apparently preferential formation of As-H bonds at 80K was believed to involve lattice strain and selective bonding on defects, produced in the Ga sub-lattice, that exposed weak- and dangling- As bond sites. The annealing results indicated a loss of As-H centers between 180 and 250K, with an activation energy of 0.5eV. Absorption by Ga-H centers increased as absorption by As-H centers decreased during annealing, and continued to increase when As-H absorption was no longer detectable. The characteristics of As-H center annealing were compared with those previously reported for atomic displacement disorder in irradiated GaAs. The release of H from As-H bonds within thermally unstable damage regions was suggested to explain the annealing loss of As-H centers. An increase in absorption by Ga-H centers, following the loss of As-H centers, was attributed to the re-trapping of H on Ga neighbors of VAs or on VAs-Asi pair defects.

H.J.Stein, J.C.Barbour: Physical Review B, 1997, 56[7], 3813-9