Gate-controlled reversible rectifying behavior investigated in a two-dimensional MoS2 diode

By using density functional theory and ab initio quantum-transport simulation, we study the Schottky barrier and the rectifying behavior of diodes consisting of the two-dimensional metal phase 1T-MoS2 and semiconductor phase 2H-MoS2. The results show that the Schottky barrier of the out-of-plane (OP) contacted MoS2 heterostructure diode is a little different from that of the in-plane (IP) contacted MoS2 heterostructure diode. The current-voltage characteristics show that the OP diode has the better rectifying behavior compared to the IP diode under the zero gate voltage. The corresponding maximum rectifier ratio of the OP Schottky barrier diode is close to 10(7) at 0.9 V bias voltage. More interestingly, we find that the gate voltage can be used to effectively control the rectifying behavior of the two diodes. The positive gate voltages can increase the current value of two Schottky barrier diodes, but weaken their rectification ratios. The negative gate voltages can reverse the rectifying direction of two Schottky barrier diodes. The above results provide good theoretical guidance for the designing of diode devices based on two-dimensional materials in the future.