Electronic Structure and Transport in Graphene Nanoribbon Heterojunctions under Uniaxial Strain: Implications for Flexible Electronics

Abstract

Graphene nanoribbons (GNRs) are highly tunable electronic materials that can be assembled to form two-dimensional (2D) nanoarchitectures with unique electronic features. In this paper, we investigate 1D and 2D GNR-based heterojunctions by combining chevron and 9-armchair GNRs together. We then investigate the electronic structure and transport of GNR heterojunctions using first-principles simulations. The coupling of chevron and 9-armchair GNRs leads to the formation of emergent electronic states at the interface due to the geometric mismatch. These states strongly control the electronic structure of the heterojunction. Doping the heterojunction with nitrogen on the edges of the chevron segment shows that these emergent states could disappear from the lowest unoccupied molecular orbital due to the band alignment of the connected GNRs. We also investigate the effect of applying uniaxial strain on the electronic characteristics of the 1D and 2D nanoarchitectures. The results show a lower bandgap and higher electronic conductance as the compressive strain is increased. The nitrogen-doped 2D structure exhibits a lower bandgap and higher electronic currents due to higher transmission pathways. Overall, these fundamental insights could help in the development of 2D GNR-based flexible and wearable devices.