Nonlinear electrical characteristics of semi-insulating GaAs

Nonlinear electrical transport processes in a semiconductor gas discharge structure with semi-insulating GaAs are studied for a wide range of gas pressures, interelectrode distances and different diameters of the photocathode areas. A primary destabilization of homogeneous state observed in a planar dc-driven structure is due to nonlinear transport properties of GaAs photocathode. GaAs samples present N-shaped negative differential conductivity under high-electric fields and the presence of the deep electronic levels of defects, the so-called EL2 centers, gives rise to the N-type-NDC of the material, as a consequence, to low-frequency oscillations in current when a dc voltage of a high enough magnitude is applied to a GaAs photocathode. It is important to note that we have experimentally investigated the above-mentioned nonlinear electrical characteristics of GaAs by a new-suggested method and our experimental findings are obviously in good agreement with estimated results reported by other independent authors. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.