Light-Emitting Two-Dimensional Ultrathin Silicon Carbide

Abstract

Two-dimensional (2D) atomic crystals, especially graphene, have received much attention. However, the main shortcoming of graphene is its zero band gap. Silicon carbide, composed of silicon and carbon, is a typical wurtzite compound semiconductor, with more than 250 alloy types. Herein, we give some evidence of the solution exfoliation of 2D SiC nanoflakes with thickness down to 0.5–1.5 nm. Transmission electron microscopy (TEM) and X-ray diffraction characterizations reveal that graphitic (0001)/(0001̅) SiC most possibly has been formed by sonication of wurtzite SiC. Graphene, which is also produced in this process, naturally forms the ultrathin substrate facilitating the TEM characterization of 2D SiC. The mechanism of this exfoliation process should be related to the surface reconstruction of wurtzite SiC into graphitic SiC. Photoluminescence spectra show a strong light-emitting ability and a quantum-confinement-induced emission peak at 373 nm for these ultrathin SiC nanosheets.