Predicted photonic band gaps in diamond-lattice crystals built from silicon truncated tetrahedrons

TL;DR

This paper predicts that diamond-lattice photonic crystals made from truncated silicon tetrahedra can exhibit wide, robust photonic band gaps, promising for integration into silicon-based photonic devices.

Contribution

It demonstrates that using truncated silicon tetrahedra significantly enhances photonic band gap widths in diamond-lattice crystals, enabling easier self-assembly and integration.

Findings

Wide band gap of 23.6% achieved with truncated tetrahedra

Band gap width is insensitive to small truncation deviations

Self-assembly of these structures is feasible for silicon photonics

Abstract

Recently, a silicon micromachining method to produce tetrahedral silicon particles was discovered. In this report we determine, using band structure calculations, the optical properties of diamond-lattice photonic crystals when assembled from such particles. We show that crystal structures built from silicon tetrahedra are expected to display small stop gaps. Wide photonic band gaps appear when truncated tetrahedral particles are used to build the photonic crystals. With truncated tetrahedral particles a band gap with a width of 23.6% can be achieved, which is more than twice as wide compared to band gaps in self-assembled diamond-lattices of hard-spheres. The width of the band gap is insensitive to small deviations from the optimal amount of truncation. This work paves the way to a novel class of silicon diamond-lattice band gap crystals that can be obtained through self-assembly. Such a self-assembly approach would allow for easy integration of these highly photonic crystals in existing silicon microfluidic and -electronic systems.