Arsenic Vacancy Formation in GaAs Annealed in Hydrogen Gas Flow

From results of the photoluminescence studies of heavily Si-doped n -type GaAs, which have followed ion implantation at 70 kV with Ar + , As + , and O + and/or annealing at 800°C in hydrogen gas flow, it is confirmed that a luminescence line near 1.4 eV which has a half-width of about 80 meV at 80 K is attributed to a Si As –V As , complex, in which a hole is not tightly bound to the complex center. Arsenic vacancy could be satisfactorily reduced by arsenic-implantation if the arsenic dose and energy are appropriately chosen. In Si-doped GaAs, an oxygen atom occupies an arsenic site if it is empty, otherwise the oxygen atom stays at an interstitial site and joins a silicon atom.