The absorption spectrum of hydrogenated silicon carbide nanocrystals from ab initio calculations

TL;DR

This study uses first principles calculations to analyze how surface reconstruction affects the absorption spectrum of hydrogenated silicon carbide nanocrystals, revealing limitations of traditional DFT methods.

Contribution

It demonstrates the impact of surface reconstruction on the absorption spectrum and highlights the inadequacy of traditional DFT in predicting absorption thresholds.

Findings

Surface reconstruction significantly alters the absorption spectrum shape.

Traditional DFT fails to accurately predict the absorption threshold.

Surface effects are crucial for understanding nanocrystal optical properties.

Abstract

The electronic structure and absorption spectrum of hydrogenated silicon carbide nanocrystals (SiCNC) have been determined by first principles calculations. We show that the reconstructed surface can significantly change not just the onset of absorption, but the \emph{shape} of the spectrum at higher energies. We found that the absorption treshold of the reconstructed SiCNs cannot be accurately predicted from traditional density functional theory calculations.