Traps in GaAs detectors (before and after irradiation) and electric field redistribution in excited SI-GaAs

We report here on investigations of non-equilibrium conductivity and different types of defects in SI-GaAs, analyzing the effects of different growth techniques and thermal treatments. The influence of local inhomogeneities on the determination of electrical properties and parameters of local levels are discussed. The interaction of dislocation related defects and their charge have been recognized as the main factors influencing non-equilibrium carrier behaviour. The GaAs irradiation effects could be analyzed in terms of formation of microinhomogeneities, with different non-equilibrium carrier drift and capture in the inhomogeneity volume and the surrounding defect-free region. The trap spectra were studied using thermally stimulated current and polarization measurements. EL2 centre modification was used to separate electron and hole traps. Data from measurements of Hall and photo-Hall effects and light-induced non-linear optical effect measurements have also been used in the analysis.