Dependence of GaAs:Si persistent photoconductivity on temperature and α-particle irradiation

We investigated the photoconductivity of GaAs:Si epilayer on SI-GaAs specimens. We measured the current from the time we switched on the illumination and after switching it off as a function of time at various temperatures from 250 to 330 K. A small persistent photoconductivity starts to appear from 250 K. At 330 K a clear positive persistent photoconductivity (PPPC) appears. The persistent photoconductivity increases with temperature. Then the specimens were irradiated with α-particles from an Am 241 source at 330 K. A change in persistent photoconductivity is observed from the dose of 6×10 12 particles/cm 2. At higher doses not only the current increases, but also the PPC duration. We try to explain these phenomena on the base of the existing theoretical models. © 2004 Elsevier Ltd. All rights reseved