Semiconducting Silicene: A Two-Dimensional Silicon Allotrope with Hybrid Honeycomb-Kagome Lattice

Silicene is recognized as a promising candidate of two-dimensional (2D) materials replacing bulk silicon in the post-CMOS era, because of its compatibility with silicon-based technologies. However, the Dirac-cone band structure, because of the honeycomb lattice, prevents pristine silicene from being applied as a semiconductor in electronic devices. Here, we propose a 2D-silicon semiconductor by introducing kagome topology into the honeycomb lattice, i.e., a hybrid honeycomb-kagome (hhk) structure that is referenced as hhk-silicene. Our first-principles calculations demonstrate the high geometric stability and excellent semiconducting properties of the hhk-silicene, which opens up an electronic bandgap comparable to that of the bulk silicon and bears an electron mobility as high as that of the honeycomb silicene. By designing a field-effect transistor based on the hhk-silicene, giant negative differential resistance and switching performance fulfilling the requirements of ITRS (International Technology Roadmap for Semiconductors) are predicted. This work opens up the possibility of rational design of 2D-silicon semiconductors by focusing on the topological lattice structures.

Automated summary

This study introduces a new hybrid honeycomb-kagome (hhk) structure into silicon lattice, proposing a novel hhk-silicene semiconductor with electronic bandgap comparable to bulk silicon and high electron mobility. By designing a field-effect transistor based on this structure, giant negative differential resistance and switching performance fulfilling the requirements of the International Technology Roadmap for Semiconductors are predicted. This work opens up the possibility of rational design of 2D-silicon semiconductors by focusing on topological lattice structures.