Parallel Logic Operations in Electrically Tunable Two-Dimensional Homojunctions

Two-dimensional materials show great potential for future electronics beyond silicon materials. Here, we report an exotic multiple-port device based on multiple electrically tunable planar p–n homojunctions formed in a two-dimensional (2D) ambipolar semiconductor, tungsten diselenide (WSe2). In this device, we prepare multiple gates consisting of a global gate and several local gates, by which electrostatically induced holes and electrons are simultaneously accumulated in a WSe2 channel, and furthermore, at the boundaries, p–n junctions are formed as directly visualized by Kelvin probe force microscopy. Therefore, in addition to the gate voltages in our device, the drain/source bias can also be used to switch the 2D WSe2 channel on/off due to the rectification effect of the formed p–n junctions. More importantly, when the voltage on the global gate electrode is altered, all p–n junctions are affected, which makes it possible to perform parallel logic operations.