Defect properties of undoped semi-insulating and Si-doped n-type GaAs annealed at different As phase pressures were studied by means of positron annihilation and Hall effect measurements. In both types of samples, formation of monovacancy-like defects during annealing was observed. The concentration of these defects increases in GaAs:Si and decreases in undoped GaAs when the As pressure increases. In GaAs:Si, the defect was earlier identified as SiGa–VGa complex, however, in undoped GaAs As vacancies were formed, which were part of defect complex.

Vacancy Formation in GaAs under Different Equilibrium Conditions. V.Bondarenko, J.Gebauer, F.Redmann, R.Krause-Rehberg: Applied Physics Letters, 2005, 87[16], 161906 (3pp)