Local Strain Engineering in Atomically Thin MoS2

• Published in: Nano letters Vol. 13; no. 11; pp. 5361 - 5366
• Main Authors: Castellanos-Gomez, Andres, Roldán, Rafael, Cappelluti, Emmanuele, Buscema, Michele, Guinea, Francisco, van der Zant, Herre S. J, Steele, Gary A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 13-11-2013
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electron states; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Excitons and related phenomena; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); atomically thin crystal; band structure; strain engineering; Molybdenum disulfide nanosheets; exciton trapping; funnel effect; Nanometer scale; Band structure; Energy gap; Electronic properties; Experimental result; Deformation; Excitons; Optoelectronic properties; Imaging; Photoluminescence; Stress effects; Nanostructures
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl402875m

Controlling the bandstructure through local-strain engineering is an exciting avenue for tailoring optoelectronic properties of materials at the nanoscale. Atomically thin materials are particularly well-suited for this purpose because they can withstand extreme nonhomogeneous deformations before rupture. Here, we study the effect of large localized strain in the electronic bandstructure of atomically thin MoS2. Using photoluminescence imaging, we observe a strain-induced reduction of the direct bandgap and funneling of photogenerated excitons toward regions of higher strain. To understand these results, we develop a nonuniform tight-binding model to calculate the electronic properties of MoS2 nanolayers with complex and realistic local strain geometries, finding good agreement with our experimental results.