Subbands and charge control in a two-dimensional electron gas field-effect transistor

Abstract

A calculation of the subband structure and charge distribution in an AlxGa1−xAs/GaAs heterojunction as a function of gate voltage at room temperature has been performed. The results show that usually about 80% of the electrons in the channel are in the lowest two subbands and describe for the first time quantitatively the transition from the simple capacitive charge control regime to the regime where the channel density is no longer controlled by the gate voltage.