DEFECT MODELS IN ELECTRON-IRRADIATED N-TYPE GAAS

1 MeV electron irradiation has been performed in degenerate, n-type (n congruent-to 2 X 10(17) cm-3), molecular beam epitaxial GaAs layers, and Hall effect measurements have been carried out during the irradiation in order to get accurate defect production data. The results have been fitted with statistical models, and are most consistent with the usual E1 (E(C)-0.045 eV) and E2 (E(C)-0.15 eV) levels being the (-/0) and (0/+) transitions of the As vacancy, respectively. Also, an acceptor well below E(C)- 0. 15 eV is produced at a much higher rate than that of E1 and E2.