Figure 2.

(a) A scanning electron micrograph showing one of the measured unipolar 3-terminal hot electron nanowire devices. The middle base electrode needs to be positioned and defined sharply between the injector and the energy filter, spaced by a distance l. Voltage V_eb biases the injector and V_bc the filter. (b) Band diagram under typical operation. The voltage V_eb lifts the energy of the emitter electrons and flattens the graded barrier, giving rise to electron injection. Ballistic electrons fly over the filter to an unbiased (V_bc = 0) collector.