Anomalous Reconfigurable-Transport in MoS₂ Transistors by Electrically-Switchable van der Waals Interfacial Dipole

Interfacial charge transfer leads to the formation of an electric dipole at the interface of a van der Waals (vdW) heterostructure. The switching of dipole polarity using an electric field provides an effective method for modulating the electronic properties of vdW systems. However, the experimental observation of switched vdW dipoles is challenging, as it is concealed by the electrostatic gating effect. In this work, the significant electrical tunability of the strong interfacial dipole formed in an insulator-semiconductor heterostructure of high-work-function BiOCl and MoS₂ are demonstrated. The heterostructured device essentially operates as a planar tunneling transistor, where band-to-band tunneling occurs within the vdW doping-defined junction, resulting in a subthreshold swing significantly lower than that of typical field effect transistors. More importantly, the anomalous reconfiguration of electronic transports is observed in MoS₂ transistors due to the switching of vdW dipole and its competition with the electrostatic gating. By varying the BiOCl thickness, the n-type, p-type, anti-ambipolar, and "W"-shaped transfer characteristics are achieved. Furthermore, a dual-gate configuration further enhances functionality of the device, enabling multi-state switching, which is of particularly interest for these applications requiring negative differential resistance. This work offers a scalable, versatile, and non-destructive strategy for tuning reconfigurable two-dimensional transistors.