Molybdenum Disulfide Transistors Bearing All-2D-Material Interfaces: Device Performance Optimization and Influences of Interfaces and Passivation Layers

Two-dimensional (2D) materials are only a few atomic layers thick, which means that these materials will be severely influenced by various non-2D-material interfaces after device fabrication. In addition to the crystallinity of the 2D materials, the main bottleneck of device performance may originate from these interfaces. With polycrystalline antimonene as the contact electrode and mono-layer MoS₂ buffer layers on the top and bottom of the mono-layer MoS₂ channel to reduce the influence from the top Al₂O₃ passivation and bottom SiO₂ dielectric layers, optimized device performances, including a field-effect mobility of 25.70 cm² V^-1·s^-1 and ON/OFF ratios >10⁵, were achieved for MoS₂ transistors that have a channel width/length of 25/5 μm, respectively. By further reducing the channel width/length to 500/660 nm, an even higher field-effect mobility of 63.80 cm² V^-1·s^-1 and ON/OFF ratios >10⁶ were achieved for the device, which were attributed to reduced carrier scattering in the polycrystalline MoS₂ channel with reduced line widths. The use of 2D-material homostructures to isolate the 2D-material channel and a deposition temperature of <100 °C to fabricate the antimonene contact facilitated the fabrication of MoS₂ transistors bearing all-2D-material interfaces is advantageous for practical applications.