Experimental Realization of Atomic Monolayer Si<sub>9</sub> C<sub>15</sub>.

Gao, Zhao-Yan; Xu, Wenpeng; Gao, Yixuan; Guzman, Roger; Guo, Hui; Wang, Xueyan; Zheng, Qi; Zhu, Zhili et al. · Adv Mater · 2022

basic_science · Level V

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Abstract

Monolayer Si<sub>x</sub> C<sub>y</sub> constitutes an important family of 2D materials that is predicted to feature a honeycomb structure and appreciable bandgaps. However, due to its binary chemical nature and the lack of bulk polymorphs with a layered structure, the fabrication of such materials has so far been challenging. Here, the synthesis of atomic monolayer Si<sub>9</sub> C<sub>15</sub> on Ru (0001) and Rh(111) substrates is reported. A combination of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), and density functional theory (DFT) calculations is used to infer that the 2D lattice of Si<sub>9</sub> C<sub>15</sub> is a buckled honeycomb structure. Monolayer Si<sub>9</sub> C<sub>15</sub> shows semiconducting behavior with a bandgap of ≈1.9 eV. Remarkably, the Si<sub>9</sub> C<sub>15</sub> lattice remains intact after exposure to ambient conditions, indicating good air stability. The present work expands the 2D-materials library and provides a promising platform for future studies in nanoelectronics and nanophotonics.