Localization of Upper-Valley Electrons in a Narrow-Bandgap Channel: a Possible Additional Mechanism of Current Increase in DA–DpHEMT

Abstract

The influence of the localization of upper-valley electrons in a narrow-bandgap channel on the drift velocity burst in Al_xGa_{1 –x}As–GaAs transistor heterostructures with double-sided doping has been theoretically estimated. It is established that the fraction of electrons passing in this case from the narrow-bandgap channel to wide-bandgap material is smaller than in the usual structures, which can lead in some cases to an increase in the electron drift velocity by up to 15%. This phenomenon can provide an additional mechanism of current increase in transistors based on heterostructures with donor–acceptor doping.