title: Effects of Uniaxial and Biaxial Strain on Few-Layered Terrace Structures of MoS₂ Grown by Vapor Transport.
abstract: One of the most fascinating properties of molybdenum disulfide (MoS2) is its ability to be subjected to large amounts of strain without experiencing degradation. The potential of MoS2 mono- and few-layers in electronics, optoelectronics, and flexible devices requires the fundamental understanding of their properties as a function of strain. While previous reports have studied mechanically exfoliated flakes, tensile strain experiments on chemical vapor deposition (CVD)-grown few-layered MoS2 have not been examined hitherto, although CVD is a state of the art synthesis technique with clear potential for scale-up processes. In this report, we used CVD-grown terrace MoS2 layers to study how the number and size of the layers affected the physical properties under uniaxial and biaxial tensile strain. Interestingly, we observed significant shifts in both the Raman in-plane mode (as high as -5.2 cm(-1)) and photoluminescence (PL) energy (as high as -88 meV) for the few-layered MoS2 under ∼1.5% applied uniaxial tensile strain when compared to monolayers and few-layers of MoS2 studied previously. We also observed slippage between the layers which resulted in a hysteresis of the Raman and PL spectra during further applications of strain. Through DFT calculations, we contended that this random layer slippage was due to defects present in CVD-grown materials. This work demonstrates that CVD-grown few-layered MoS2 is a realistic, exciting material for tuning its properties under tensile strain.
authors.affiliation: Sensors & Electron Devices Directorate, U.S. Army Research Laboratory , Adelphi, Maryland 20783, United States.|Computational and Information Sciences Directorate, U.S. Army Research Laboratory , Aberdeen Proving Ground, Maryland 21005, United States.
authors.forename: Amber
authors.initials: A
authors.lastname: McCreary
authors.forename: Rudresh
authors.initials: R
authors.lastname: Ghosh
authors.affiliation: Sensors & Electron Devices Directorate, U.S. Army Research Laboratory , Adelphi, Maryland 20783, United States.
authors.forename: Matin
authors.initials: M
authors.lastname: Amani
authors.affiliation: Department of Materials Science and Engineering, and Institute of Materials Science, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Karel-Alexander N
authors.initials: KA
authors.lastname: Duerloo
authors.forename: Ankit
authors.initials: A
authors.lastname: Sharma
authors.forename: Karalee
authors.initials: K
authors.lastname: Jarvis
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Evan J
authors.initials: EJ
authors.lastname: Reed
authors.affiliation: Department of Materials Science and Engineering, and Institute of Materials Science, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Avinash M
authors.initials: AM
authors.lastname: Dongare
authors.forename: Sanjay K
authors.initials: SK
authors.lastname: Banerjee
authors.forename: Mauricio
authors.initials: M
authors.lastname: Terrones
authors.affiliation: Computational and Information Sciences Directorate, U.S. Army Research Laboratory , Aberdeen Proving Ground, Maryland 21005, United States.
authors.forename: Raju R
authors.initials: RR
authors.lastname: Namburu
authors.affiliation: Sensors & Electron Devices Directorate, U.S. Army Research Laboratory , Adelphi, Maryland 20783, United States.
authors.forename: Madan
authors.initials: M
authors.lastname: Dubey
keywords: CVD; Raman; few-layer; interlayer sliding; molybdenum disulfide; photoluminescence; strain engineering