Electrical Contact Analysis of Multilayer MoS₂ Transistor With Molybdenum Source/Drain Electrodes

Abstract

We demonstrate two-dimensional (2D) multilayered molybdenum disulfide (MoS2) transistor with molybdenum (Mo) side and edge contacts, which is deposited by using DC-sputtering method. It exhibits field-effect mobility of 23.9 cm 2 /Vs and on/off ratio of 10 6 in a linear region. Current-voltage study under different temperatures (300-393 K) reveals that Mo-MoS2 transistor shows a band transport characteristics, and a Schottky barrier height of 0.14 eV is estimated using thermionic emission theory. Finally, side and edge contact of Mo-MoS2 are confirmed through transmission electron microscope (TEM) analysis. Our results not only show that Mo can be an alternative contact metal to other low work-function metals but also that edge contact may play an important role in resolving performance degradation over thickness increase of MoS2 channel layer.

Progress in Contact, Doping and Mobility Engineering of MoS2: An Atomically Thin 2D Semiconductor

“…They found that the electrical performance of their 96-layer or 67 nm thick MoS 2 FET (µ FE~2 4 cm 2 /V-s) was similar to few-layer (3-5L) MoS 2 FETs with Mo top contacts (µ FE~2 6-27 cm 2 /V-s). This clearly suggests that the detrimental effect of R int was greatly minimized even though the MoS 2 was 67 layers thick, thanks to the formation of edge contacts (due to conformal Mo deposition by DC-sputtering) that injected carriers deep into the constituent layers of the multilayer MoS 2 device [278]. Chai et al developed a "passivation first, metallization second" technique for fabricating pure edge contacts to two types of back-gated MoS 2 -based heterostructures wherein the MoS 2 was first encapsulated in-between dielectrics: Al 2 O 3 /MoS 2 /SiO 2 and hBN/MoS 2 /hBN.…”

High Mobility MoS2 Transistor with Low Schottky Barrier Contact by Using Atomic Thick h‐BN as a Tunneling Layer

“…Contact resistance is one of the key factors attributing to the loss of mobility since the formation of a Schottky barrier for electron injection greatly limits the FETs performance . A number of past works have been conducted to improve the contact resistance recently . For example, phase engineered MoS 2 can greatly reduce the contact resistance while the metastable 1T phase MoS 2 limits its application .…”

Preparation of MoS2 Nanopetals by RF Magnetron Sputtering and Electron-Beam Irradiation

“…Most of the preparation and device application of MoS 2 were focused on ultra-thin films. However, a few previous reports of multilayer MoS 2 have suggested the potential for its device applications [7][8][9] since multilayer structure of MoS 2 is insensitive to the extrinsic factors [10] and enhances the current flow of FET [11].…”