Instabilities in LEC GaAs Schottky barrier pixel detector imaging arrays

We present room temperature measurements of inhomogeneities and instabilities in a GaAs pixel detector array at high bias voltage. The evolution of the inhomogeneity structure and its change due to increase of bias voltage was investigated. The dark current image was analyzed. It is proposed that a cellular structure of higher and lower conductivity regions is responsible for the inhomogeneities and their spatial and temporal instability. The electrical inhomogeneity in LEC SI-GaAs and its dependence on electric field was qualitatively investigated by using a hybridized GaAs pixel detector and a model of the influence of crystal inhomogeneity on the measured parameters of the detector array is proposed.