Effect of hydrogenation on defect levels in bulk n-GaAs

Abstract

The hydrogenation effects on the defect levels existing in bulk n-GaAs were investigated by deep-level transient spectroscopy and photoluminescence. The three electron traps of the GaAs bulk samples were observed, and their activation energies wereE _c — 0.35 eV (E1), 0.56 eV (E2), and 0.81 eV (E3). After hydrogenation at 250 °C for 3 h, the electron trap atE _c — 0.35 eV was almost completely passivated and a new trap (EN1) atE _c — 0.43 eV was observed. As a result of furnace annealing for 5 min at 300 °C, the EN1 trap disappeared, and the E3 trap passivated by hydrogenation reappeared. In particular, the trap E1 recovered to 90%. The photoluminescence measurements of the hydrogenated samples show that the germanium-related peak was passivated, and the intensity of the dominant bound exciton peak increased remarkably. After a thermal annealing for 15 min at 300 °C, the original intensity of the germanium-related peak was restored.