1. A multiplexing system comprising: at least two electronically scannable multiplexing devices that are independently controlled and are stacked relative to each other, wherein the at least two scannable multiplexing devices are interconnected in series, wherein an output of a first scannable multiplexing device is used to control accessibility of a subsequent multiplexing device and wherein each scannable multiplexing device comprises: a scanning region; two gates disposed at different locations relative to the scanning region; wherein upon application of potentials to the two gates, two depletion regions within the scanning region, interact to generate a conducting channel within the scanning region; and wherein the conducting channel is controllably scannable within the scanning region by varying the potentials applied to the two gates.