Research progress and challenges of two dimensional MoS₂ field effect transistors

Abstract

This review paper gives an outline of the recent research progress and challenges of 2D TMDs material MoS2 based device, that leads to an interesting path towards approaching the electronic applications due to its sizeable band gap. This review presents the improvement of MoS2 material as an alternate to a silicon channel in a transistor with its excellent energy band gap, thermal conductivity, and exclusive physical properties that are expected to draw attention to focusing on semiconducting devices for most futuristic applications. We discuss the band structure of MoS2 for a different number of layers with its structure, and various synthesis techniques of the MoS2 layer are also reviewed. The MoS2 based field effect transistor has attracted a great deal of attention due to its excellent properties such as mobility, on/off current ratio, and maximum on-current of the devices. The transition of mobility as a function of temperature and thickness dependence are also discussed. However, the mobility of MoS2 material is large in bulk form and lower in monolayer form. The use of a high-k gate dielectric in MoS2 FET is used to enhance the mobility of the device. Different metal contact engineering and different doping techniques were deployed to achieve low contact resistance. This review paper focuses on various aspects of layered TMDs material MoS2 based field effect transistors.

2D Metallic Transition‐Metal Dichalcogenides: Structures, Synthesis, Properties, and Applications

“…[ 15–20 ] As the key members of 2D materials, TMDs with the formula MX 2 (where M is a transition metal atom of group IV–VIII and X is the chalcogen atom including S, Se, or Te) have recently drawn intense scientific and engineering interest because of the advantages of diverse crystal structures, ultrathin thickness, layer‐dependent band gap, as well as new functional applications in electronics, optoelectronics, catalysis, energy storage, and many others. [ 21–26 ] Moreover, TMDs are usually classified into four types according to electronic band structures: metallic TMDs, semimetallic TMDs, semiconducting s‐TMDs with various energy band gaps, and insulating TMDs. It is important to note that semimetals have metallic properties in some cases, so we will summarize metallic TMDs and semimetallic TMDs as m‐TMDs in this review.…”

Gate Stack Engineering in MoS2 Field‐Effect Transistor for Reduced Channel Doping and Hysteresis Effect

“…[ 10 ] Corresponding device processing techniques suitable for TMDs have also been developed rapidly, but various challenges still exist. [ 11–15 ] One main obstacle is that carriers in ultrathin channels are extremely sensitive to the ambient environment due to the inherent atomic thickness of 2DLMs. This leads to a complicated interaction among multiple processing steps, such as source–drain formation and dielectric layer deposition.…”

A wafer-scale synthesis of monolayer MoS2 and their field-effect transistors toward practical applications

“…Commonly used dielectric layers include inorganic materials and some polymers, such as SiO 2 , Al 2 O 3 , HfO 2 , ZrO 2 , PVDF, PMMA, and CaF 2 . 74–81 Few-layer graphene, h-BN and MoSe 2 are also considered as dielectrics to improve the field effect mobility in MoS 2 -FET. 82–84 Another key issue is contact and channel engineering in the FET device fabrication based on large-area 2D MoS 2 films.…”