Band engineering and elastic properties of strained armchair graphene nanoribbons: semiconductor vs metallic characteristics

TL;DR

This study uses density functional theory to demonstrate how applying strain to hydrogen-passivated armchair graphene nanoribbons can precisely tune their electronic properties from semiconductor to metallic and back, while also affecting their mechanical behavior.

Contribution

It provides a detailed analysis of strain effects on bandgap tuning and mechanical properties of hydrogen-passivated armchair graphene nanoribbons, enabling potential straintronic device applications.

Findings

Strain can switch nanoribbons between semiconductor and metallic states.

Hydrogen passivation influences out-of-plane deformations under strain.

Mechanical properties are significantly affected by applied strain.

Abstract

An odd number of zigzag edges in armchair graphene nanoribbons and their mechanical properties (e.g., Young's modulus, Poisson ratio and shear modulus) have potential interest for bandgap engineering in graphene based optoelectronic devices. In this paper, we consider armchair graphene nanoribbons passivated with hydrogen at the armchair edges and then apply the strain for tuning the bandgaps. Using density functional theory calculations, our study finds that the precise control of strain can allow tuning the bandgap from semiconductor to mettalic and then again switching back to semiconductor. In addition, we also show that the strained graphene nanoribbon passivated with hydrogen molecules can have large out-of-plane deformations demonstrating the properties of relaxed shape graphene. We express the strain induced by hydrogen in terms of binding energy. Finally, we characterise the effect of strain on the mechanical properties that can be used for making straintronic devices based on graphene nanoribbons.