Energy band gaps in graphene nanoribbons with corners

¹ Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, Qatar Foundation PO Box 5825, Doha, Qatar
² Institute of Physics, Czȩstochowa University of Technology - Ave. Armii Krajowej 19, 42200 Czȩstochowa, Poland
³ Institute for Molecules and Materials CNRS UMR 6283, University of Maine - Ave. Olivier Messiaen, 72085 Le Mans, France
⁴ American University of the Middle East, College of Engineering and Technology - Egaila, Kuwait

Received: 8 March 2016
Accepted: 25 May 2016

Abstract

In the present paper, we study the relation between the band gap size and the corner-corner length in representative chevron-shaped graphene nanoribbons (CGNRs) with 120° and 150° corner edges. The direct physical insight into the electronic properties of CGNRs is provided within the tight-binding model with phenomenological edge parameters, developed against recent first-principle results. We show that the analyzed CGNRs exhibit inverse relation between their band gaps and corner-corner lengths, and that they do not present a metal-insulator transition when the chemical edge modifications are introduced. Our results also suggest that the band gap width for the CGNRs is predominantly governed by the armchair edge effects, and is tunable through edge modifications with foreign atoms dressing.