HIGH-TEMPERATURE BALLISTIC TRANSPORT OBSERVED IN ALGAAS INGAAS/GAAS SMALL 4-TERMINAL STRUCTURES/

Four-terminal structures are fabricated by focused-ion-beam (FIB) scan ning on an AlGaAs/InGaAs/GaAs modulation doped structure. The large ca rrier density of this system results in small depletion spreading and a 260-nm-square four-terminal structure is successfully formed. The be nd resistance of this structure indicates that ballistic coupling betw een two facing terminals remains up to room temperature. Thermal broad ening of electron energy enhances the ballistic nature of the system a t high temperature.