Tuning the bandgap of exfoliated InSe nanosheets by quantum confinement

Abstract

Strong quantization effects and tuneable near-infrared photoluminescence emission are reported in mechanically exfoliated crystals of γ-rhombohedral semiconducting InSe. The optical properties of InSe nanosheets differ qualitatively from those reported recently for exfoliated transition metal dichalcogenides and indicate a crossover from a direct to an indirect band gap semiconductor when the InSe flake thickness is reduced to a few nanometers. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.