Uncovering the Effects of Metal Contacts on Monolayer MoS2

Abstract

Metal contacts are a key limiter to the electronic performance of two-dimensional (2D) semiconductor devices. Here we present a comprehensive study of contact interfaces between seven metals (Y, Sc, Ag, Al, Ti, Au, Ni, with work functions from 3.1 to 5.2 eV) and monolayer MoS2 grown by chemical vapor deposition. We evaporate thin metal films onto MoS2 and study the interfaces by Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, and electrical characterization. We uncover that, 1) ultrathin oxidized Al dopes MoS2 n-type (> 2x10^12 1/cm^2) without degrading its mobility, 2) Ag, Au, and Ni deposition causes varying levels of damage to MoS2 (broadening Raman E' peak from <3 1/cm to >6 1/cm), and 3) Ti, Sc, and Y react with MoS2. Reactive metals must be avoided in contacts to monolayer MoS2, but control studies reveal the reaction is mostly limited to the top layer of multilayer films. Finally, we find that 4) thin metals do not significantly strain MoS2, as confirmed by X-ray diffraction. These are important findings for metal contacts to MoS2, and broadly applicable to many other 2D semiconductors.

References in corpus (16)

• Bandgap Engineering of Strained Monolayer and Bilayer MoS2
• Two-dimensional transition metal dichalcogenides under electron irradiation: defect production and doping
• Symmetry-dependent phonon renormalization in monolayer MoS2 transistor
• Improved Contacts to MoS2 Transistors by Ultra-High Vacuum Metal Deposition
• Strain tuning of optical emission energy and polarization in monolayer and bilayer MoS2
• Fano resonance and spectrally modified photoluminescence enhancement in monolayer MoS2 integrated with plasmonic nanoantenna array
• Air Stable Doping and Intrinsic Mobility Enhancement in Monolayer $Mo{S}_2$ by Amorphous $Ti{O}_x$ Encapsulation
• Optical detection of strain and doping inhomogenieties in single layer MoS2
• A- and B-Exciton Photoluminescence Intensity Ratio as a Measure of Sample Quality for Transition Metal Dichalcogenide Monolayers
• Intrinsic Electrical Transport and Performance Projections of Synthetic Monolayer MoS2 Devices
• Contact Engineering High Performance n-Type MoTe2 Transistors
• Probing the Intrinsic Optical Quality of CVD Grown MoS2
• Ultra Low Specific Contact Resistivity in Metal-Graphene Junctions via Atomic Orbital Engineering
• Layer Dependent Interfacial Transport and Optoelectrical Properties of MoS2 on Ultra-flat Metals
• An Inside Look at the Ti-MoS2 Contact in Ultra-thin Field Effect Transistor with Atomic Resolution
• Titanium Contacts to Graphene: Process-Induced Variability in Electronic and Thermal Transport

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