Computational insights and the observation of SiC nanograin assembly: towards 2D silicon carbide

Abstract

While an increasing number of two-dimensional (2D) materials, including graphene and silicene, have already been realized, others have only been predicted. An interesting example is the two-dimensional form of silicon carbide (2D-SiC). Here, we present an observation of atomically thin and hexagonally bonded nanosized grains of SiC assembling temporarily in graphene oxide pores during an atomic resolution scanning transmission electron microscopy experiment. Even though these small grains do not fully represent the bulk crystal, simulations indicate that their electronic structure already approaches that of 2D-SiC. This is predicted to be flat, but some doubts have remained regarding the preference of Si for sp${}^3$ hybridization. Exploring a number of corrugated morphologies, we find completely flat 2D-SiC to have the lowest energy. We further compute its phonon dispersion, with a Raman-active transverse optical mode, and estimate the core level binding energies. Finally, we study the chemical reactivity of 2D-SiC, suggesting it is like silicene unstable against molecular absorption or interlayer linking. Nonetheless, it can form stable van der Waals-bonded bilayers with either graphene or hexagonal boron nitride, promising to further enrich the family of two-dimensional materials once bulk synthesis is achieved.

arXiv comment10 pages, 5 figures, 4 supplementary figures

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• Defect-driven tunable electronic and optical properties of two-dimensional silicon carbide
• Vacancy-related color centers in twodimensional silicon carbide monolayers
• Theoretical study of quantum emitters in two-dimensional silicon carbide monolayer
• Quantum effects in two-dimensional silicon carbide
• Structure and Electronic States of a Graphene Double Vacancy with an Embedded Si Dopant
• Unfolding optical transition weights of impurity materials for first-principles LCAO electronic structure calculations
• Structure and energetics of embedded Si patterns in graphene
• Characterization of Silicon Carbide Biphenylene Network through G0W0-BSE Calculations