Lateral tunneling, ballistic transport, and spectroscopy in a two-dimensional electron gas

Abstract

We report a direct observation, via electron energy spectroscopy, of lateral tunneling and lateral ballistic-electron transport in a two-dimensional electron gas (2D EG). This was accomplished through the use of a novel transistor structure employing two potential barriers, induced by 50-nm wide metal gates deposited on a GaAs/AlGaAs selectively doped heterostructure. Hot electrons with very narrow energy distributions (\ensuremath{\simeq}5 meV wide) have been observed to ballistically traverse 2D EG regions \ensuremath{\simeq}170 nm wide with a mean free path of about 480 nm.