Boron and nitrogen impurities in SiC nanoribbons: an ab initio investigation

TL;DR

This study uses ab initio density-functional theory to analyze how boron and nitrogen impurities affect the electronic properties of hydrogen-terminated SiC nanoribbons with zigzag and armchair edges, revealing edge localization and changes in conductivity.

Contribution

It provides new insights into impurity localization preferences and their effects on the electronic and magnetic properties of SiC nanoribbons.

Findings

Boron and nitrogen prefer edge sites in SiC nanoribbons.

Boron substitution does not alter semiconducting behavior in armchair ribbons.

Nitrogen can turn zigzag ribbons from half-metallic to metallic.

Abstract

Using ab initio calculations based on density-functional theory we have performed a theoretical investigation of substitutional boron and nitrogen impurities in silicon carbide (SiC) nanoribbons. We have considered hydrogen terminated SiC ribbons with zigzag and armchair edges. In both systems we verify that the boron and nitrogen atoms energetically prefer to be localized at the edges of the nanoribbons. However, while boron preferentially substitutes a silicon atom, nitrogen prefers to occupy a carbon site. In addition, our electronic-structure calculations indicate that (i) substitutional boron and nitrogen impurities do not affect the semiconducting character of the armchair SiC nanoribbons, and (ii) the half-metallic behavior of the zigzag nanoribbons is maintained in the presence of substitutional boron impurities. In contrast, nitrogen atoms occupying edge carbon sites transform half-metallic zigzag nanoribbons into metallic systems.