Lateral tunneling and ballistic transport in two-dimensional electron gas devices defined by nanostructure gates

Abstract

Novel, laterally configured, tunneling hot electron transfer amplifier (THETA) devices have been formed using nanostructure metal gates to induce potential barriers separating emitter, base, and collector regions in a two-dimensional electron gas. The gates were formed by a liftoff technique using PMMA resist and a high resolution electron beam writing tool. Lateral electron tunneling has been directly observed, using electron energy spectroscopy, through potential barriers under metal gates as wide as 52 nm. The energy distribution of the hot electrons was only ≂5 meV wide. Certain gate configurations were found to increase the fraction of emitted electrons which reached the collector. Current gain as high as 105 was observed. This is better than the best results previously obtained with vertical THETA devices.