Parallel Logic\nOperations in Electrically Tunable\nTwo-Dimensional Homojunctions

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