Influence of Low Energy α-particle Fluxes on the Photoconductivity of GaAs

摘要

In the present work, we study the influence of small energy α-particles (0,96 MeV) on the photoconductivity in order to construct a detector for small fluxes of low energy α-particles irradiation. Photocurrent measurements were carried out at room temperature (T=300K), before and after irradiation, on Semi-insulated (SI) GaAs specimens, with epilayer of low resistivity Si doped GaAs. Analyzing, by the Origin 7.0 Pro program, the experimental data I_ph = f(E_photons), where I_ph is the difference between the current under illumination and the dark current, we found three Gaussian curves. We irradiated the specimen, using Am²⁴¹ as a source of α-particles, in equal time intervals succeeding small differences in the α-particles fluxes. We measured the photocurrent using photons of energies corresponding to the peaks of the above referred curves before and after each irradiation. We repeated the measurements for total duration of 6 hours corresponding to 119,88·10⁷ α-particles/cm². We observed that the relation I_ph = f(N) is linear for all specimens, where with N we denote the flux.