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.