Exfoliation of Nanoribbons from Bulk van der Waals Crystals for Optical and Electronic Characterization

A.P. Saunders, A. Krayev, V. Chen, A.C. Johnson, A.S. McKeown-Green, H.J. Zeng, E. Pop, F. Liu
Stanford University,
United States

Keywords: 2D materials, mechanical exfoliation, TERS, electrostatic force microscopy


Nanoribbons are an important family of quantum materials with properties beyond their monolayer and bulk counterparts. However, their experimental exploration has been limited due to the lack of high-throughput production techniques. In this work, we demonstrate a direct and universally applicable preparatory method, analogous to scotch tape exfoliation in versatility by obtaining single-crystalline, flat, and parallel-aligned monolayer nanoribbons directly from bulk 2D crystals with high yield and large aspect ratio. Exfoliated nanoribbons include MoS2, WS2, MoSe2, WSe2, MoTe2, WTe2, ReS2, and hBN, with nanoribbon morphology assessed via atomic force microscopy. We identified distinct electrical and excitonic properties in transition metal dichalcogenide (TMDC) nanoribbons, which display increased compressive strain in narrower ribbons. We demonstrate an increased influence from edge states in nanoribbons through electronic transport characteristics, electrostatic force microscopy, and tip-enhanced raman spectroscopy (TERS). This transferrable preparation technique offers the potential to control nanoribbon morphology and dimensionality while providing a central avenue for experimental characterization.