Devices with negative differential transconductance (NDT) and negative differential resistance (NDR) have shown a strong potential for digital electronics with high information density due to their N-shaped current–voltage (I–V) characteristics leading to multiple threshold voltages ( Vths). The 2D materials, such as graphene, hBN, MoS2, WS2, etc., offer an attractive platform to achieve NDT and NDR because of the absence of dangling bonds on the surface, leading to a high-quality interface between the layers. The 2D materials' unique property of the weak van der Waals (vdW) interactions without dangling bonds on the heterostructure devices shows the way for the applications more than-Moore devices. This review holds a well-timed overview of 2D materials-based devices to develop future multi-valued logic (MVL) circuits exhibiting high information density. Notably, the recent advances in emerging 2D materials are reviewed to support the directions for future research on MVL applications.

Molybdenum disulfide ( MoS2) has been one of the most promising members of transition-metal dichalcogenides materials. Attributed to the excellent electrical performance and special physical properties, MoS2 has been broadly applied in semiconductor devices, such as field effect transistors (FETs). At present, the exploration of further improving the performance of MoS2- based FETs (such as increasing the carrier mobility and scaling) has encountered a bottleneck, and the application of high-κ gate dielectrics has become an effective approach to change this situation. Atomic layer deposition (ALD) enables high-quality integration of MoS2 and high-κ gate dielectrics at the atomic level. In this review, we summarize recent advances in the fabrication of two-dimensional MoS2 FETs using ALD high-κ materials as gate dielectrics. We first briefly discuss the research background of MoS2 FETs. Second, we expound the electrical and other essential properties of high-κ gate dielectrics, which are essential to the performance of MoS2 FETs. Finally, we focus on the advances in fabricating MoS2 FETs with ALD high-κ gate dielectrics on MoS2, as well as the optimized ALD processes. In addition, we also look forward to the development prospect of this field.

Interest in eco-friendly materials with high efficiencies is increasing significantly as science and technology undergo a paradigm shift toward environment-friendly and sustainable development. MXenes, a class of two-dimensional inorganic compounds, are generally defined as transition metal carbides or nitrides composed of few-atoms-thick layers with functional groups. Recently MXenes, because of their desirable electrical, thermal, and mechanical properties that emerge from conductive layered structures with tunable surface terminations, have garnered significant attention as promising candidates for energy storage applications (e.g., supercapacitors and electrode materials for Li-ion batteries), water purification, and gas sensors. In this review, we introduce MXenes and describe their properties and research trends by classifying them into two main categories: transition metal carbides and nitrides, including Ti-based MXenes, Mo-based MXenes, and Nb-based MXenes.