Effects of Uniaxial and Biaxial Strain on Few-Layered Terrace Structures of MoS2 Grown by Vapor Transport

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• 作者：Amber McCreary ; Rudresh Ghosh ; Matin Amani ; Jin Wang ; Karel-Alexander N. Duerloo ; Ankit Sharma ; Karalee Jarvis ; Evan J. Reed ; Avinash M. Dongare ; Sanjay K. Banerjee ; Mauricio Terrones ; Raju R. Namburu ; Madan Dubey
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：March 22, 2016
• 年：2016
• 卷：10
• 期：3
• 页码：3186-3197
• 全文大小：763K
• ISSN：1936-086X

文摘

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.