Optically induced current oscillation in a modulation-doped field-effect transistor embedded with InAs quantum dots

The output characteristics of a modulation-doped GaAs/AlGaAs field-effect transistor with InAs quantum dots (QDs) embedded in the barrier layer (QDFET) have been studied at low temperature. Optically induced current oscillation in the output current–voltage (I–V) curves has been found under the near-infrared light illumination. It is ascribed to the recombination of real space transferred electrons and photoexcited holes captured by the QDs. Furthermore, InAs QDs layer can also capture electrons and act as a nano-floating gate, which causes a bistability in the two-dimensional electron gas (2DEG) conductance. Our results suggest that the QDFET is a promising candidate for developing phototransistor or logic circuits.