Mobility Enhancement in CVD-Grown Monolayer MoS<sub>2</sub> Via Patterned Substrate-Induced Nonuniform Straining.

Kayal, Arijit; Dey, Sraboni; G, Harikrishnan; Nadarajan, Renjith; Chattopadhyay, Shashwata; Mitra, Joy · Nano Lett · 2023

basic_science · Level V

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Abstract

The extraordinary mechanical properties of two-dimensional transition-metal dichalcogenides make them ideal candidates for investigating strain-induced control of various physical properties. Here we explore the role of nonuniform strain in modulating optical, electronic, and transport properties of semiconducting, chemical vapor deposited monolayer MoS<sub>2</sub>, on periodically nanostructured substrates. A combination of spatially resolved spectroscopic and electronic properties explore and quantify the differential strain distribution and carrier density on a monolayer, as it conformally drapes over the periodic nanostructures. The observed accumulation in electron density at the strained regions is supported by theoretical calculations which form the likely basis for the ensuing ×60 increase in field effect mobility in strained samples. Though spatially nonuniform, the pattern-induced strain is shown to be readily controlled by changing the periodicity of the nanostructures thus providing a robust yet useful macroscopic control on strain and mobility in these systems.