Tunable Band Structures of Polycrystalline Graphene by External and Mismatch Strains

Abstract

Lacking a band gap largely limits the application of graphene in electronic devices. Previous study shows that grain boundaries (GBs) in polycrystalline graphene can dramatically alter the electrical properties of graphene. Here, we investigate the band structure of polycrystalline graphene tuned by externally imposed strains and intrinsic mismatch strains at the GB by density functional theory (DFT) calculations. We found that graphene with symmetrical GBs typically has zero band gap even with large uniaxial and biaxial strain. However, some particular asymmetrical GBs can open a band gap in graphene and their band structures can be substantially tuned by external strains. A maximum band gap about 0.19 eV was observed in matched-armchair GB (5, 5) | (3, 7) with a misorientation of θ=13o when the applied uniaxial strain increases to 9%. Although mismatch strain is inevitable in asymmetrical GBs, it has a small influence on the band gap of polycrystalline graphene.

7 pages, 4 figures

References in corpus (12)

• The electronic properties of graphene
• Energy Band Gap Engineering of Graphene Nanoribbons
• Energy Gaps in Graphene Nanoribbons
• Substrate-induced band gap opening in epitaxial graphene
• Graphene Nano-Ribbon Electronics
• Electronic States of Graphene Nanoribbons
• A tight-binding approach to uniaxial strain in graphene
• Electronic transport in polycrystalline graphene
• Topological Defects in Graphene: Dislocations and Grain Boundaries
• Origins of anomalous electronic structures of epitaxial graphene on silicon carbide
• Heat Conduction across Monolayer and Few-Layer Graphenes
• Strain induced conductance modulation in graphene grain boundary