Analyzing the Carrier Mobility in Transition-metal Dichalcogenide MoS2 Field-effect Transistors

Abstract

Transition-metal dichalcogenides (TMDCs) are important class of two-dimensional (2D) layered materials for electronic and optoelectronic applications, due to their ultimate body thickness, sizable and tunable bandgap, and decent theoretical room-temperature mobility of hundreds to thousands cm2/Vs. So far, however, all TMDCs show much lower mobility experimentally because of the collective effects by foreign impurities, which has become one of the most important limitations for their device applications. Here, taking MoS2 as an example, we review the key factors that bring down the mobility in TMDC transistors, including phonons, charged impurities, defects, and charge traps. We introduce a theoretical model that quantitatively captures the scaling of mobility with temperature, carrier density and thickness. By fitting the available mobility data from literature over the past few years, we are able to obtain the density of impurities and traps for a wide range of transistor structures. We show that interface engineering such as oxide surface passivation, high-k dielectrics and BN encapsulation could effectively reduce the impurities, leading to improved device performances. For few-layer TMDCs, we analytically model the lopsided carrier distribution to elucidate the experimental increase of mobility with the number of layers. From our analysis, it is clear that the charge transport in TMDC samples is a very complex problem that must be handled carefully. We hope that this Review can provide new insights and serve as a starting point for further improving the performance of TMDC transistors.

61 pages, 9 figures, Advanced Functional Materials, in press

References in corpus (18)

• Electric Field Effect in Atomically Thin Carbon Films
• Two Dimensional Atomic Crystals
• Boron nitride substrates for high-quality graphene electronics
• Valley polarization in MoS2 monolayers by optical pumping
• Synthesis of Large-Area MoS2 Atomic Layers with Chemical Vapor Deposition
• High Performance Single Layered WSe2 p-FETs with Chemically Doped Contacts
• Integrated Circuits Based on Bilayer MoS2 Transistors
• Two dimensional semiconductors with possible high room temperature mobility
• Electrical Transport Properties of Single-Layer WS2
• Towards Intrinsic Charge Transport in Monolayer Molybdenum Disulfide by Defect and Interface Engineering
• Device Perspective for Black Phosphorus Field-Effect Transistors: Contact Resistance, Ambipolar and Scaling
• Two-dimensional Quasi-Freestanding Molecular Crystals for High-Performance Organic Field-Effect Transistors
• Bandgap and doping effects in MoS2 measured by Scanning Tunneling Microscopy and Spectroscopy
• Large Thermoelectricity via Variable Range Hopping in Chemical Vapor Deposition Grown Single-layer MoS2
• Probing the Electron States and Metal-Insulator Transition Mechanisms in Atomically Thin MoS2 Based on Vertical Heterostructures
• Mobility enhancement and temperature dependence in top-gated single-layer MoS2
• Contact Research Strategy for Emerging Molybdenum Disulfide and Other Two-Dimensional Field-effect Transistors
• High-frequency, scaled MoS2 transistors

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