Native acceptor levels in Ga‐rich GaAs

A photoluminescence, photocapacitance, and thermal annealing study of Ga‐rich GaAs has revealed the complex behavior of acceptor levels at 68–77 and 200 meV above the valence band. The concentration of all levels is enhanced by Ga‐rich growth conditions, however, only the 77‐ and 200‐meV levels formed preferably in n‐type GaAs are consistent with a double‐acceptor model of the gallium antisite defect. In p‐type GaAs the 68‐meV level associated with a different single‐acceptor defect is dominant. It is argued that the inhibited formation of double‐acceptor GaAs defects in p‐type crystals is caused by the Fermi‐energy control of the defect formation.