Coulomb engineering of the bandgap and excitons in two-dimensional materials

• Published in: Nature communications Vol. 8; no. 1; p. 15251
• Main Authors: Raja, Archana, Chaves, Andrey, Yu, Jaeeun, Arefe, Ghidewon, Hill, Heather M., Rigosi, Albert F., Berkelbach, Timothy C., Nagler, Philipp, Schüller, Christian, Korn, Tobias, Nuckolls, Colin, Hone, James, Brus, Louis E., Heinz, Tony F., Reichman, David R., Chernikov, Alexey
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04.05.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/119/995; 639/925/357/1018; electronic properties and materials; Energy; Engineering; Graphene; Humanities and Social Sciences; MATERIALS SCIENCE; multidisciplinary; Physics; Quantum dots; Science; Science (multidisciplinary); two-dimensional materials; New York; United States > US; California
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms15251

The ability to control the size of the electronic bandgap is an integral part of solid-state technology. Atomically thin two-dimensional crystals offer a new approach for tuning the energies of the electronic states based on the unusual strength of the Coulomb interaction in these materials and its environmental sensitivity. Here, we show that by engineering the surrounding dielectric environment, one can tune the electronic bandgap and the exciton binding energy in monolayers of WS 2 and WSe 2 by hundreds of meV. We exploit this behaviour to present an in-plane dielectric heterostructure with a spatially dependent bandgap, as an initial step towards the creation of diverse lateral junctions with nanoscale resolution. Electronic bandgap tuning in semiconductors enables key functionalities in solid-state devices. Here, the authors present a strategy to control the bandgap of atomically thin WS 2 and WSe 2 semiconductors via manipulation of the surrounding dielectric environment rather than by modifications of the materials themselves.