Depletion charge measurements by tunneling spectroscopy GaAs-GaAlAs field-effect transistors

Abstract

The subband energies on GaAs-GaAlAs field-effect transistor samples were measured by tunneling spectroscopy using a structure, where the tunneling process starts from an accumulation layer, and a conventional structure, where the electrons tunnel from a metal electrode into the two-dimensional electron gas. Self-consistent calculations were performed to determine the depletion charge from the measured subband energies. Furthermore, the influence of a backgate voltage was investigated both experimentally and theoretically. As far as we know, this is the first direct determination of the depletion charge in GaAs-GaAlAs field-effect transistor structures.