Electronic transport properties of transition metal dichalcogenide field-effect devices: surface and interface effects

Abstract

Recent explosion of interest in two-dimensional (2D) materials research has led to extensive exploration of physical and chemical phenomena unique to this new class of materials and their technological potential. Atomically thin layers of group 6 transition metal dichalcogenides (TMDs) such as MoS2 and WSe2 are remarkably stable semiconductors that allow highly efficient electrostatic control due to their 2D nature. Field effect transistors (FETs) based on 2D TMDs are basic building blocks for novel electronic and chemical sensing applications. Here, we review the state-of-the-art of TMD-based FETs and summarize the current understanding of interface and surface effects that play a major role in these systems. We discuss how controlled doping is key to tailoring the electrical response of these materials and realizing high performance devices. The first part of this review focuses on some fundamental features of gate-modulated charge transport in 2D TMDs. We critically evaluate the role of surfaces and interfaces based on the data reported in the literature and explain the observed discrepancies between the experimental and theoretical values of carrier mobility. The second part introduces various non-covalent strategies for achieving desired doping in these systems. Gas sensors based on charge transfer doping and electrostatic stabilization are introduced to highlight progress in this direction. We conclude the review with an outlook on the realization of tailored TMD-based field-effect devices through surface and interface chemistry.

The ambipolar transport behavior of WSe2 transistors and its analogue circuits

“…The mobility increase should be related to both the increased density of state inducing a smaller Schottky barrier (discussed later in Fig. 3d) and the screened interfacial charged impurities inducing a weaker scattering 31 . Moreover, the bandgap of WSe 2 decreases as the thickness increases 32 , which is also one of the key reasons for the enhancement of electrical performance.…”

Electronics and optoelectronics of quasi-1D layered transition metal trichalcogenides

“…Simple photodetectors display ultrahigh responsivisties (up to 3000 A/W) without optimization 53 . Increased photoconductive gain could be achieved through the realization of hybrid devices that benefit from coupling to quantum dots 199 or functionalized molecules 200 . While time resolved measurements have been performed on bulk-like nanoribbons (3 μm thick) 173 , atomically thin crystals have yet to be investigated and it remains to be seen whether the TMTCs present similar many body interactions (exciton-exciton annihilation) as the TMDCs in atomically thin samples [201][202][203][204][205] .…”

Intrinsic Charge Carrier Mobility in Single-Layer Black Phosphorus

“…Recently, many new two-dimensional (2D) materials have attracted attention [8], such as hexagonal boron nitride [9], stoichiometric graphene derivatives [10,11], transition-metal dichalcogenides [9,12], and black phosphorus (BP) [13]. All these materials are typically more defective than graphene and are characterized by significantly smaller electron mobility; therefore, much less is known experimentally on their intrinsic transport properties [14][15][16][17][18][19][20][21].Comprehensive theories have been developed to describe the mechanism of phonon scattering in graphene [7]. The application of those is, however, not straightforward to systems with reduced symmetries that give rise to anisotropy of electronic and vibrational properties.…”