Two-step chemical vapor deposition synthesis of NiTe₂-MoS₂ vertical junctions with improved MoS₂ transistor...

The primary challenge for the widespread application of two-dimensional (2D) electronics is to achieve satisfactory electrical contacts because, during the traditional metal integration process, difficulties arise due to inevitable physical damage and selective doping. Two-dimensional metal-semiconductor junctions have attracted attention for the potential application to achieve reliable electrical contacts in future atomically thin electronics. Here we demonstrate the van der Waals epitaxial growth of 2D NiTe₂-MoS₂ metal-semiconductor vertical junctions where the upper NiTe₂ selectively nucleates at the edge of the underlying MoS₂. Optical microscopy (OM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and scanning transmission electron microscope (STEM) studies confirmed that NiTe₂-MoS₂ metal-semiconductor vertical junctions had been successfully synthesized. The electrical properties of the NiTe₂-contacted MoS₂ field-effect transistors (FETs) showed higher field-effect mobilities (μ _FE) than those with deposited Cr/Au contacts. This study demonstrates an effective pathway to improved MoS₂ transistor performance with metal-semiconductor junctions.