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Nano Research

Article Title

Electronic structure, optical properties, and lattice dynamics in atomically thin indium selenide flakes

Authors

Juan F. Sánchez-Royo, ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain
Guillermo Muoz-Matutano, ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain
Mauro Brotons-Gisbert, ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain
Juan P. Martínez- Pastor, ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain
Alfredo Segura, ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain MALTA-Consolider Team, Institut de Ciència dels Materials-Dpto. de Física Aplicada, Universitat de València, E-46100 Burjassot (València), Spain
Andrés Cantarero, ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain
Rafael Mata, ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain
Josep Canet-Ferrer, ICMUV, Instituto de Ciencia de Materiales, Universidad de Valencia, P.O. Box 22085, 46071 Valencia, Spain
Gerard Tobias, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Barcelona, Spain
Enric Canadell, Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Barcelona, Spain
Jose Marqués-Hueso, Institute of Photonics and Quantum Science, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, UK
Brian D. Gerardot, Institute of Photonics and Quantum Science, SUPA, Heriot-Watt University, Edinburgh EH14 4AS, UK

Keywords

indium selenide, two-dimensional flakes, micro-Raman spectroscopy, micro-photoluminescence, electronic structure

Abstract

The progressive stacking of chalcogenide single layers gives rise to two- dimensional semiconducting materials with tunable properties that can be exploited for new field-effect transistors and photonic devices. Yet the properties of some members of the chalcogenide family remain unexplored. Indium selenide (InSe) is attractive for applications due to its direct bandgap in the near infrared, controllable p- and n-type doping and high chemical stability. Here, we reveal the lattice dynamics, optical and electronic properties of atomically thin InSe flakes prepared by micromechanical cleavage. Raman active modes stiffen or soften in the flakes depending on which electronic bonds are excited. A progressive blue-shift of the photoluminescence peaks is observed for decreasing flake thickness (as large as 0.2 eV for three single layers). First-principles calculations predict an even larger increase in the bandgap, 0.40 eV, for three single layers, and as much as 1.1 eV for a single layer. These results are promising from the point of view of the versatility of this material for optoelectronic applications at the nanometer scale and compatible with Si and III–V technologies.

Graphical Abstract

Publisher

Tsinghua University Press

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