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Improved gas sensing activity in structurally defected bilayer graphene
Dept of Physics, Faculty of Sciences, University of Shahid Chamran, Ahwaz, Iran.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.ORCID iD: 0000-0002-3161-4326
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2012 (English)In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 23, no 50, 50550- p.Article in journal (Refereed) Published
Abstract [en]

Graphene is a two-dimensional material with a capability of gas sensing, which is here shown to be drastically improved by inducing gentle disorder in the lattice. We report that by using a focused ion beam technique, controlled disorder can be introduced into the graphene structure through Ga + ion irradiation. This disorder leads to an increase in the electrical response of graphene to NO 2 gas molecules by a factor of three in an ambient environment (air). Ab initio density functional calculations indicate that NO 2 molecules bind strongly to Stone–Wales defects, where they modify electronic states close to the Fermi level, which in turn influence the transport properties. The demonstrated gas sensor, utilizing structurally defected graphene, shows faster response, higher conductivity changes and thus higher sensitivity to NO 2 as compared to pristine graphene.

Place, publisher, year, edition, pages
2012. Vol. 23, no 50, 50550- p.
National Category
Atom and Molecular Physics and Optics Engineering and Technology
Research subject
Engineering Science with specialization in Materials Science
Identifiers
URN: urn:nbn:se:uu:diva-186253DOI: 10.1088/0957-4484/23/50/505501ISI: 000311855300014OAI: oai:DiVA.org:uu-186253DiVA: diva2:572755
Available from: 2012-11-28 Created: 2012-11-28 Last updated: 2017-12-07
In thesis
1. Influence of defects and impurities on the properties of 2D materials
Open this publication in new window or tab >>Influence of defects and impurities on the properties of 2D materials
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Graphene, the thinnest material with a stable 2D structure, is a potential alternative for silicon-based electronics. However, zero band gap of graphene causes a poor on-off ratio of current thus making it unsuitable for logic operations. This problem prompted scientists to find other suitable 2D materials. Creating vacancy defects or synthesizing hybrid 2D planar interfaces with other 2D materials, is also quite promising for modifying graphene properties. Experimental productions of these materials lead to the formation of possible defects and impurities with significant influence in device properties. Hence, a detailed understanding of the effects of impurities and defects on the properties of 2D systems is quite important.

In this thesis, detailed studies have been done on the effects of impurities and defects on graphene, hybrid graphene/h-BN and graphene/graphane structures, silicene and transition metal dichalcogenides (TMDs) by ab-initio density functional theory (DFT). We have also looked into the possibilities of realizing magnetic nanostructures, trapped at the vacancy defects in graphene, at the reconstructed edges of graphene nanoribbons, at the planar hybrid h-BN graphene structures, and in graphene/graphane interfaces. A thorough investigation of diffusion of Fe adatoms and clusters by ab-initio molecular dynamics simulations have been carried out along with the study of their magnetic properties. It has been shown that the formation of Fe clusters at the vacancy sites is quite robust. We have also demonstrated that the quasiperiodic 3D heterostructures of graphene and h-BN are more stable than their regular counterpart and certain configurations can open up a band gap. Using our extensive studies on defects, we have shown that defect states occur in the gap region of TMDs and they have a strong signature in optical absorption spectra. Defects in silicene and graphene cause an increase in scattering and hence an increase in local currents, which may be detrimental for electronic devices. Last but not the least, defects in graphene can also be used to facilitate gas sensing of molecules as well as and local site selective fluorination.  

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. 100 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1432
Keyword
2D Materials, Defects on 2D materials, Impurities on 2D materials
National Category
Condensed Matter Physics Atom and Molecular Physics and Optics
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-300970 (URN)978-91-554-9699-9 (ISBN)
Public defence
2016-11-11, Polhemsalen Ång/10134, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2016-10-19 Created: 2016-08-16 Last updated: 2016-11-03

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Publisher's full texthttp://stacks.iop.org/0957-4484/23/i=50/a=505501

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Blom, TobiasJafri, S H MHaldar, SoumyajyotiBhandary, SumantaEriksson, OlleSanyal, BiplabLeifer, Klaus

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