Minigap-induced negative differential resistance in multilayer MoS2 -based tunnel junctions

Abstract

Despite extensive research, the high-energy band properties of transition metal dichalcogenides remain unexplored. Here, we reveal that a multilayer MoS2-based tunnel junction exhibits substantial negative differential resistance (NDR) owing to the presence of a minigap, which is the energy gap between the upper and lower bands of the valence band at the Γ point. We fabricated a highly p-doped multilayer p+−MoS2/h-BN/p+−MoS2 tunnel junction. When a bias is applied across the junction, holes at the Fermi level at the Γ point in the valence band of the source-side p+−MoS2 resonantly tunnel to the drain-side p+−MoS2 with momentum conservation. When the energy of the injected hole coincides with the minigap of the drain-side p+−MoS2, the tunneling conductance is suppressed; thus, NDR is observed in the current-voltage characteristics. We identified minigap-induced NDR over a broad range of MoS2 thicknesses, including the bulk, that was observable even at room temperature. Published by the American Physical Society 2024