Room Temperature Negative Differential Resistance with High Peak Current in MoS 2 /WSe 2 Heterostructures.

Two-dimensional transition metal dichalcogenide (2D TMD) semiconductors allow facile integration of p- and n-type materials without a lattice mismatch. Here, we demonstrate gate-tunable n- and p-type junctions based on vertical heterostructures of MoS 2 and WSe 2 using van der Waals (vdW) contacts. The p-n junction shows negative differential resistance (NDR) due to Fowler-Nordheim (F-N) tunneling through the triangular barrier formed by applying a global back-gate bias ( V GS ). We also show that the integration of hexagonal boron nitride ( h -BN) as an insulating tunnel barrier between MoS 2 and WSe 2 leads to the formation of sharp band edges and unintentional inelastic tunnelling current. The devices based on vdW contacts, global V GS , and h -BN tunnel barriers exhibit NDR with a peak current ( I peak ) of 315 μA, suggesting that the approach may be useful for applications.