Low-frequency current pulses in low-conductivity GaAs

Properties of current pulses in low-conductivity planar bulk GaAs containing Cu and Fe were investigated, and the generation mechanism of the pulses are discussed. Both the amplitude and period of the current pulses depend upon the applied voltage. The pulse is strongly influenced by the illumination of specimens with light of a tungsten lamp. The period of the current pulses cannot be related to the transit time of the electrons between the two electrodes. The phenomenon can be understood qualitatively by periodic excitation and trapping processes of electrons in deep impurity levels.