Strain modulated band gap of edge passivated armchair graphene nanoribbons

TL;DR

This study uses first principles calculations to explore how strain affects the band gap of edge-passivated armchair graphene nanoribbons, revealing periodic and shifted variations, including a strain-induced direct-to-indirect transition.

Contribution

It provides new insights into strain effects on band gaps of AGNRs with different edge passivations, highlighting a strain-induced transition in O-passivated nanoribbons.

Findings

Band gap of H-passivated AGNRs varies periodically with strain.

O and OH passivation shift the zigzag pattern of band gap variation.

O-passivated AGNRs undergo a direct-to-indirect band gap transition at ~5% tensile strain.

Abstract

First principles calculations were performed to study strain effects on band gap of armchair graphene nanoribbons (AGNRs)with different edge passivation, including H, O, and OH group. The band gap of the H-passivated AGNRs shows a nearly periodic zigzag variation under strain. For O and OH passivation, the zigzag patterns are significantly shifted by a modified quantum confinement due to the edges. In addition, the band gap of the O-passivated AGNRs experiences a direct-to-indirect transition with sufficient tensile strain (~5%). The indirect gap reduces to zero with further increased strain.