Device simulation study of multilayer MoS₂ Schottky barrier field-effect transistors

Abstract Molybdenum disulfide (MoS₂) is a representative two-dimensional layered transition-metal dichalcogenide semiconductor. Layer-number-dependent electronic properties are attractive in the development of nanomaterial-based electronics for a wide range of applications including sensors, switches, and amplifiers. MoS₂ field-effect transistors (FETs) have been studied as promising future nanoelectronic devices with desirable features of atomic-level thickness and high electrical properties. When a naturally n-doped MoS₂ is contacted with metals, a strong Fermi-level pinning effect adjusts a Schottky barrier and influences its electronic characteristics significantly. In this study, we investigate multilayer MoS₂ Schottky barrier FETs (SBFETs), emphasizing the metal-contact impact on device performance via computational device modeling. We find that p-type MoS₂ SBFETs may be built with appropriate metals and gate voltage control. Furthermore, we propose ambipolar multilayer MoS₂ SBFETs with asymmetric metal electrodes, which exhibit gate-voltage dependent ambipolar transport behavior through optimizing metal contacts in MoS₂ device. Introducing a dual-split gate geometry, the MoS₂ SBFETs can further operate in four distinct configurations: p − p, n − n, p − n, and n − p. Electrical characteristics are calculated, and improved performance of a high rectification ratio can be feasible as an attractive feature for efficient electrical and photonic devices.