Tuning gap in bilayer graphene
Year: 2008
Type: preprint
Abstract: Opening, in a controllable way, energy gap in graphene electron spectrum is necessary for many potential applications, including an efficient carbon-based transistor. We have shown that this can be reached by a chemical functionalization of bilayer graphene. Using various dopants, such as H, F, Cl, Br, OH, CN, CCH, NH2, COOH, and CH3 one can vary the gap value smoothly between 0.64 and 3 eV and the state with the energy gap is stable corresponding to the lowest-energy configurations. Graphene, a recently discovered two-dimensional allotrope of carbon (for review, see Refs.[1, 2, 3]) is a very promising material for future development of electronics, due to its planar geometry and a very high electron mobility [1]. Charge carriers in graphene mimic ultrarelativistic Dirac fermions which creates a new, unexpected bridge between condensed matter physics and quantum electrodynamics (for review, see Ref.[4]). At the same time, some of quantum ultrarelativistic phenomena which make graphene so attractive scientifically can be considered as obstacles for applications. In particular, the chiral “Klein ” tunneling [5] makes p−n−p (or n−p−n) junctions unusually transparent. This does not allow to lock the junction making its use as a transistor problematic. The bilayer graphene [6] is more preferable in this sense since the angular range of anomalous transparency is narrower there [5] but only opening a real gap in electron spectrum would be a radical solution
Source: arXiv (Cornell University)
Authors: Danil W. Boukhvalov, M. I. Katsnelson
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2137107777