Ballistic transport at room temperature in deeply etched cross-junctions

Abstract
We measured the transmission through nanoscopic cross-junctions at variable temperature and bias. The devices were prepared by deep etching through a two-dimensional electron gas in InGaAs/InP samples. Our experiments show that the transmission characteristic is partly ballistic even at room temperature. The measurements are analysed in terms of an equivalent network, and the involved resistances are related to the electrons' mean free path. Different scattering mechanisms are considered to account for the transition from ballistic to diffusive transport.