Generation and the characteristics of current pulses from alloyed-type low-conductivity bulk GaAs

Current pulses with frequencies in the vicinity of 1 kHz were observed in low-conductivity copper-doped GaAs. The coherent current pulses were obtained by applying an ac half-sinusoid voltage to low-conductivity bulk GaAs samples with indium ohmic contacts. The repetition rate increased as the applied voltage was increased. Illumination of the specimen surface or change in ambient temperature had a strong effect on the current pulses. The current pulses are due to ionization of deep levels and are compared to the microplasma pulses observed in Si and Ge p-n junctions.