Impact-ionization of excitons and application to gate-controlled bistable switching

Exciton impact-ionization effects on low temperature photocurrent were investigated in Ge pin-MIS triodes. A simple model, taking into account the exciton impact-ionization process, was given to account for the observed anomalous temperature dependence and field dependence of the photocurrent on the device. The feasibility of the exciton impact-ionization due to the gate field was checked on the MIS-structure. On this device, gate-controlled bistable switching behaviour was expected to be obtained and was experimentally demonstrated. (author)