Tuning the Bandgap of Exfoliated InSe Nanosheets by Quantum Confinement

摘要

The discovery of single-atomic layer graphene has led to a surge of interest in other anisotropic crystals with strong in-plane bonds and weak, van der Waals-like, inter-layer coupling. A variety of two-dimensional (2D) crystals with high crystalline quality and stable properties under ambient conditions have been investigated recently. These include layers of large band gap insulators such as boron nitride and oxides, and materials with smaller band gaps such as transition metal dichalcogenides (e.g., MoS_2, MoSe_2, WS_2) and Ⅲ-Ⅵ compounds (e.g., GaS and GaSe). Interest in these systems is motivated partly by the possibility of combining them with graphene to create 2D electronic devices, e.g., field effect transistors with high on-off switching ratios and memory cells. More importantly, material systems with strong radiative recombination, specific dielectric properties, a band gap that can be adjusted by changing the layer thickness could offer opportunities for innovative device architectures in nanoelec-tronics and optoelectronics.