Prediction of Silicon-Based Layered Structures for Optoelectronic Applications

TL;DR

This paper uses particle swarm optimization to predict new silicon-based layered structures with tunable electronic properties for optoelectronic applications, including hydrogenated variants with potential in LEDs and solar cells.

Contribution

It introduces a PSO-based method for designing Q2D materials and identifies novel hydrogenated silicon layers with desirable optoelectronic properties.

Findings

New Si bi-layer structure with lower energy than previous models

Hydrogenation creates Si8H2 and Si6H2 with quasi-direct band gaps

Potential for these materials in LEDs and photovoltaic devices

Abstract

A method based on the particle swarm optimization (PSO) algorithm is presented to design quasi-two-dimensional (Q2D) materials. With this development, various single-layer and bi-layer materials in C, Si, Ge, Sn, and Pb were predicted. A new Si bi-layer structure is found to have a much-favored energy than the previously widely accepted configuration. Both single-layer and bi-layer Si materials have small band gaps, limiting their usages in optoelectronic applications. Hydrogenation has therefore been used to tune the electronic and optical properties of Si layers. We discover two hydrogenated materials of layered Si8H2 and Si6H2 possessing quasi-direct band gaps of 0.75 eV and 1.59 eV, respectively. Their potential applications for light emitting diode and photovoltaics are proposed and discussed. Our study opened up the possibility of hydrogenated Si layered materials as next-generation optoelectronic devices.