Electron energy spectroscopy and the observation of ballistic transport of hot electrons in the plane of a 2DEG

The authors report the first successful fabrication of a lateral hot-electron transistor. Using energy spectroscopy, they have demonstrated the existence of ballistic transport in the plane of a 2DEG. The structure has been made by deposition of two metallic gates, each some 50 nm long, separated by 80-200 nm, on a selectively doped high-mobility GaAs/AlGaAs heterostructure. By applying negative bias to the gates, two potential barriers were formed under them that divided the plane into three regions-injection, transport, and collection-all contacted with ohmic contacts. One barrier served as a tunneling injector while the other played the role of the spectrometer. Operating the device as a hot-electron theta device and performing energy spectroscopy, hot-electron distributions, no more than 5 meV wide, were measured at the collector.