Unidirectional electron flow in a nanometer-scale semiconductor channel: A self-switching device

By tailoring the boundary of a narrow semiconductor channel to break its symmetry, we have realized a type of nanometer-scale nonlinear device, which we refer to as self-switching device (SSD). An applied voltage $V$ not only changes the potential profile along the channel direction, but also either widens or narrows the effective channel depending on the sign of $V.$ This results in a diode-like characteristic but without the use of any doping junction or barrier structure. The turn-on voltage can also be widely tuned from virtually zero to more than 10 V, by simply adjusting the channel width. The planar and two-terminal structure of the SSD also allows SSD-based circuits to be realized by only one step of lithography.