Mesoscopic structures with GE quantum dots in SI for single-photon detectors

Abstract

The results of investigation of photostimulated current switching during irradiation of mesoscopic structures based on Ge quantum dots in Si by weak infrared fluxes are presented. The small dimensions of the channel (approximately 70–200 nm) provide an opportunity to observe giant photoconductivity fluctuations which are due to the strong dependence of the hopping current on the filling of quantum dots by charge carriers. Replacing the silicon substrate with silicon-on-insulator made it possible to exclude the predominance of band conduction over hopping conduction at high temperatures and increase the photodetection temperature from 4.2 to approximately 100 K. The obtained results are the basis for the creation of a single-photon detector in a wide wavelength range.