Study by Raman Spectroscopy of the Induced Radiation Damage in GaAs:Cr Exposed to 20 MeV Electron Beam

Abstract

Raman spectroscopy has been used to search for evidence of possible radiation damage that takes place in a radiation detector based on chromium-compensated gallium arsenide semiconductor material when exposed to a 20 MeV electron beam. The Raman spectra measured before and after irradiation were deconvoluted and their intercomparative analysis demonstrate that important processes stimulated by radiation were certainly taking place in the material. These processes lead to the relaxation of the structure tensional state, the enhancement in crystallinity, and a decrease in the concentration of free carriers, which in the studied sample volume reaches 2.31%. The observed changes should be related to the generation of new Frenkel-type defects in the arsenic sublattice, and to stimulated by radiation changes in the quantity and quality of pre-existing more complex defects.