EFFECT OF HYDROGENATION ON DEFECT LEVELS IN BULK N-GAAS

The hydrogenation effects on the defect levels existing in bulk n-GaAs were investigated by deep-level transient spectroscopy and photolumin escence. The three electron traps of the GaAs bulk samples were observ ed, and their activation energies were E(c) - 0.35 eV (E1), 0.56 eV (E 2), and 0.81 eV (E3). After hydrogenation at 250-degrees-C for 3 h, th e electron trap at E(c) - 0.35 eV was almost completely passivated and a new trap (EN1) at E(c) - 0.43 eV was observed. As a result of furna ce annealing for 5 min at 300-degrees-C, the EN1 trap disappeared, and the E3 trap passivated by hydrogenation reappeared. In particular, th e trap E1 recovered to 90%. The photoluminescence measurements of the hydrogenated samples show that the germanium-related peak was passivat ed, and the intensity of the dominant bound exciton peak increased rem arkably. After a thermal annealing for 15 min at 300-degrees-C, the or iginal intensity of the germanium-related peak was restored.