Photorefractive measurements on electron-irradiated semi-insulating GaAs

Abstract

We present photorefractive measurements at 1.06 μm and 1.3 μm performed in electron-irradiated GaAs. Irradiation with electrons of kinetic energies ≥1 MeV introduces intrinsic electrically active defects which modify the Fermi-level position and allow to modify the electron-hole competition mechanism of the photorefractive effect. Furthermore, it is shown that the optical absorption in the 1.3–1.5 μm spectral range can be increased, which might allow to enlarge the useful spectral range of GaAs towards optical telecommunication windows. The native and irradiation-induced defects are assessed by electron paramagnetic resonance and optical absorption spectroscopy conducted at T=300 K and 77 K. The direct influence of an irradiation-induced mid-gap defect on the photorefractive effect is experimentally and theoretically demonstrated.