Gallium vacancy related defects in silicon doped GaAs grown at low temperatures

Point defects and complexes in silicon doped GaAs grown at low temperatures were investigated. Large differences between the donor and carrier concentrations imply that the crystals contain high concentrations of compensating defects. The detection of Si GaV Ga pairs confirms the expectation that they are gallium vacancies and their concentration appears to be controlled by the Fermi level or silicon concentration. The lattice expansion of the low temperature GaAs is related to the concentration of As Ga antisite related defects which do not appear to affect significantly the electrical properties of the material. The annealing behaviour may be explained by the nucleation of Si clustering by V Ga related defects.