High-lying thermally excited subbands of two-dimensional electron gases in GaAs/AlGaAs heterojunction for modulation-doped field-effect transistor

Abstract

The cyclotron resonance of two-dimensional electron gases was directly measured on a modulation-doped field-effect transistor structure by the gate voltage ratio spectroscopy. The intersubband energies between the lowest subband and the subbands with quantum index up to i=5 were determined by resonant subband-Landau-level coupling (RSLC) under relatively low magnetic field. The experimental results were in good agreement with the self-consistent calculations including the depolarization shift and exciton-like effect corrections. The quantum index dependence of the level splitting due to the RSLC was discussed.