Controlling\nCarrier Transport in Vertical MoTe₂/MoS₂ van\nder Waals Heterostructures

Abstract

Two-dimensional\n(2D) transition-metal dichalcogenide (TMDC)-based\nsemiconducting van der Waals (vdW) heterostructures are considered\nas potential candidates for next-generation nanoelectronics due to\ntheir unique and tunable properties. Controlling the carrier type\nand band alignment in 2D TMDCs and their vdW heterostructures is critical\nfor realizing heterojunctions with the desired performances and functionalities.\nIn this report, controlling the carrier type and band alignment in\na vertical MoTe₂/MoS₂ heterojunction is presented\nvia thickness engineering and surface charge transfer doping. A highly\nrectifying p–n diode and a nonrectifying n–n junction\nare obtained with different MoTe₂ thicknesses due to their\ndifferent doping conditions. A vertical tunnel diode is subsequently\nachieved with a controlled oxygen plasma treatment, which selectively\ninduces degenerate p-type doping to MoTe₂, whereas the\nintrinsic n-type characteristic of MoS₂ is maintained during\nthe treatment. These techniques to realize multifunctional diodes\nare universal and applicable to emerging nanoelectronics based on\n2D materials.