Irradiation-induced defects in p-type GaAs.

Electron irradiation at room temperature in p-italic-type vapor-phase-epitaxy-grown GaAs produces a series of traps labeled H-italic0, H-italic1, H-italic2, H-italic3, H-italic4, and H-italic5 situated at, respectively, 0.06, 0.25, 0.42, 0.54, 0.79, and 0.85 eV above the valence-band maximum E-italic/sub v-italic/. Their introduction rates as a function of the energy of irradiation and their annealing behavior have been studied using deep-level transient spectroscopy. From a comparison of the introduction rate and the annealing kinetics of H-italic1 with electron traps produced by irradiation in n-italic-type material, we deduced that this trap is associated with the arsenic vacancy-interstitial pair. The other traps (H-italic2, H-italic3, H-italic4, and H-italic5) are complexes of impurities with the arsenic interstitial, I-italic/sub As/, due to the fact that I-italic/sub As/ is mobile under irradiation. From the annealing kinetics of these defects we deduce the activation energy associated with the I-italic/sub As/ mobility (0.5 +- 0.15 eV) in p-italic-type GaAs. Finally, we also demonstrate that the E-italic traps situated at 0.045, 0.140, 0.30 eV below the conduction-band minimum (labeled E-italic1, E-italic2, E-italic3, respectively) present in electron-irradiated n-italic-type GaAs are also present in p-italic-type material and we have verified that these defects have the thermal stability expected from studies in n-italic-type GaAs,more » i.e., associated with the charge-state effect.« less