Molecular doping and band-gap opening of bilayer graphene.
Samuels, AJ and Carey, JD (2013) Molecular doping and band-gap opening of bilayer graphene. ACS Nano, 7 (3). pp. 2790-2799.
ACS Nano 7, 2790 (2013).pdf - Accepted version Manuscript
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The ability to induce an energy band gap in bilayer graphene is an important development in graphene science and opens up potential applications in electronics and photonics. Here we report the emergence of permanent electronic and optical band gaps in bilayer graphene upon adsorption of π electron containing molecules. Adsorption of n- or p-type dopant molecules on one layer results in an asymmetric charge distribution between the top and bottom layers and in the formation of an energy gap. The resultant band gap scales linearly with induced carrier density though a slight asymmetry is found between n-type dopants, where the band gap varies as 47 meV/10(13) cm(-2), and p-type dopants where it varies as 40 meV/10(13) cm(-2). Decamethylcobaltocene (DMC, n-type) and 3,6-difluoro-2,5,7,7,8,8-hexacyano-quinodimethane (F2-HCNQ, p-type) are found to be the best molecules at inducing the largest electronic band gaps up to 0.15 eV. Optical adsorption transitions in the 2.8-4 μm region of the spectrum can result between states that are not Pauli blocked. Comparison is made between the band gaps calculated from adsorbate-induced electric fields and from average displacement fields found in dual gate bilayer graphene devices. A key advantage of using molecular adsorption with π electron containing molecules is that the high binding energy can induce a permanent band gap and open up possible uses of bilayer graphene in mid-infrared photonic or electronic device applications.
|Divisions :||Faculty of Engineering and Physical Sciences > Electronic Engineering > Advanced Technology Institute|
|Date :||26 March 2013|
|Identification Number :||10.1021/nn400340q|
|Uncontrolled Keywords :||bilayer graphene, band gap graphene, broken inversion symmetry, molecular doping graphene, F2-HCNQ, DDQ, TTF, cobaltocene, DMC, F4-TCNQ, Decamethylcobaltocene, density of states, ab initio calculations, tight binding calculations, spin-polarised molecules, optical transitions, band engineering, band structure, effective mass|
|Related URLs :|
|Additional Information :||This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Nano, copyright © American Chemical Society after peer review and technical editing by the publisher.To access the final edited and published work see http://dx.doi.org/10.1021/nn400340q.|
|Depositing User :||Symplectic Elements|
|Date Deposited :||23 Apr 2013 17:51|
|Last Modified :||09 Jun 2014 13:12|
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