Probing the density of states in a metal-oxide-semiconductor field-effect transistor

Tunneling spectroscopy was used to probe the density of states in a metal-oxide-semiconductor field-effect transistor that has tunneling contacts for the source/drain electrodes. For long channel transistors, the density of states of the two-dimensional gas exhibits a logarithmic dependence, consistent with weak electron interactions in the diffusive regime. For smaller devices deviations from this dependence were observed and attributed to screening from the nearby source/drain electrodes.