Structural Evolution and Optoelectronic Applications of Multilayer Silicene

TL;DR

This paper uses first-principles calculations and a new optimization algorithm to explore the structural evolution and optoelectronic properties of multilayer silicene, revealing stable phases and promising applications in solar cells and optical communications.

Contribution

It introduces a novel global optimization method to identify stable multilayer silicene phases and analyzes their structural and optoelectronic properties with implications for 2D materials.

Findings

Rich stable multilayer silicene phases discovered

Critical thickness of four layers for structural stability identified

Multilayer silicene exhibits excellent optoelectronic properties for solar and optical applications

Abstract

Despite the recent progress on two-dimensional multilayer materials (2DMM) with weak interlayer interactions, the investigation on 2DMM with strong interlayer interactions is far from its sufficiency. Here we report on first-principles calculations that clarify the structural evolution and optoelectronic properties of such a 2DMM, multilayer silicene. With our newly developed global optimization algorithm, we discover the existence of rich dynamically stable multilayer silicene phases, the stability of which is closely related to the extent of sp3 hybridization that can be evaluated by the average bonds and effective bond angles. The stable Si(111) surface structures are obtained when the silicene thickness gets up to four, showing the critical thickness for the structural evolution. We also find that the multilayer silicene with pi-bonded surfaces present outstanding optoelectronic properties for the solar cells and optical fiber communications due to the incorporation of sp2-type bonds in the sp3-type bonds dominated system. This study is helpful to complete the picture of structure and related property evolution of 2DMM with strong interlayer interactions.