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arXiv · 1307.1720

Blue shifting of the A exciton peak in folded monolayer 1H-MoS2

Frank J. Crowne·Matin Amani·A. Glen Birdwell·Matthew L. Chin·Terrance P. O'Regan·Sina Najmaei·Zheng Liu·Pulickel M. Ajayan·Jun Lou·Madan Dubey
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Abstract

The large family of layered transition-metal dichalcogenides is widely believed to constitute a second family of two-dimensional (2D) semiconducting materials that can be used to create novel devices that complement those based on graphene. In many cases these materials have shown a transition from an indirect bandgap in the bulk to a direct bandgap in monolayer systems. In this work we experimentally show that folding a 1H molybdenum disulphide (MoS2) layer results in a turbostratic stack with enhanced photoluminescence quantum yield and a significant shift to the blue by 90 meV. This is in contrast to the expected 2H-MoS2 band structure characteristics, which include an indirect gap and quenched photoluminescence. We present a theoretical explanation to the origin of this behavior in terms of exciton screening.

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Frank J. Crowne, Matin Amani, A. Glen Birdwell, Matthew L. Chin, Terrance P. O'Regan, Sina Najmaei, Zheng Liu, Pulickel M. Ajayan, Jun Lou, Madan Dubey. 2013-07-05. Blue shifting of the A exciton peak in folded monolayer 1H-MoS2. https://doi.org/10.1103/physrevb.88.235302

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