Superdiffusion in semiconductors: Dynamics of radiation-enhanced superdiffusion

A three-layered system composed of GaAs (layer 3)/Si(Zn)//Si(Zn)/GaAs (layer 1) was used in this study. Si(Zn)/GaAs consists of Si(Zn) evaporation-deposited on GaAs wafers. The overlying layer was in contact with only one other Si(Zn) layer. The surface of layer 3 (GaAs) was irradiated with 750 keV and 7 MeV electrons, respectively. Electron irradiation of the wafer (layer 3) created Frenkel defects and electron-hole pairs. Interstitials of displaced atoms in the overlayer migrated to the substrate interface. Mobility-enhanced diffusion by recombination of electron-hole pairs can also occur. Residual defects in layers 1 and 3 after irradiation were athermally annealed by electron-hole recombination-enhanced defect reactions. Furthermore, new, sharp photoluminescence spectra of the neutral acceptor-bound exciton peaks appear in both layers 1 and 3, without thermal annealing