Identification of electron-irradiation defects in semi-insulating GaAs by normalized thermally stimulated current measurements

Primary defects induced by 1 MeV electron irradiation have been quantitatively studied in semi-insulating (SI) GaAs by using normalized thermally stimulated current spectroscopy, a new technique. Defects identical to (or similar to) those known in the thermally stimulated current literature as T{sub 6}{sup {asterisk}}(0.13 eV), T{sub 5}(0.34 eV), and T{sub 4}(0.31 eV) are produced at rates 0.70, 0.08, and 0.23 cm{sup {minus}1}, respectively; T{sub 5} is also a strong trap in unirradiated SI GaAs. The defects T{sub 6}{sup {asterisk}} and T{sub 4} correspond closely to the irradiation-induced traps E2(0.14 eV) and E3(0.30 eV), studied extensively by deep-level transient spectroscopy and Hall-effect measurements and assigned to the As vacancy. We thus infer that traps T{sub 6}{sup {asterisk}} and T{sub 4} (and probably also T{sub 5}) in SI GaAs have As-vacancy character. {copyright} {ital 1997} {ital The American Physical Society}