The electronic transport properties of polycrystalline graphene with various vacancy defect configurations: tight-binding simulations

Title
The electronic transport properties of polycrystalline graphene with various vacancy defect configurations: tight-binding simulations
Authors
전영인전영민이석조운조
Keywords
graphene; defect; tight-binding
Issue Date
2014-10
Publisher
International Symposium on Transparent Conductive Materials
Citation
, PS2-8
Abstract
Graphene has attracted great attention as a promising transparent electrode due to its excellent transparency and electronic mobility. In large-scale applications for touch screens, solar cells etc., it is inevitably produced in a polycrystalline form where electrical transport between single-crystal grains could be affected by scattering at the grain boundary (GB). However, previous experimental studies have not shown decisive results on this GB scattering. One detected no measurable electrical resistance from GBs within instrument limits and found very weak correlation between the average grain size and overall device mobility whereas the other reported the significant influence of GBs. It has recently been indicated that such divergent behaviors of GBs are attributed to the different structural qualities of GBs. To address this controversial issue, the present work investigates the electron transport properties of polycrystalline graphene (PG) for a range of vacancy defect configurations in nano-sized devices by using π-orbital tight-binding model combined with nonequilibrium Green function formulism. For a graphene device with a channel length of 5–6 nm, we obtain the current of ~4.5 μA and the differential conductance of 19.3 μS under the bias voltage of 0.5 V for a channel composed of PG. These values are comparable to 7.3 μA and ~32.0 μS of a single-crystalline graphene (SG) channel, which are calculated under the same condition. Special focus is placed on the influences of the number, size, and location of vacancy defects on the electron transport of PG and these aspects are explored systematically. Noticeably we find that PG can serve as a good conducting material even with some vacancies (the line density of 0.55/nm along the GB) yielding the current of 2.1–3.9 nA and the differential conductance of 9.6–18.0 nS. Finally, the effects of donor and acceptor doping
URI
http://pubs.kist.re.kr/handle/201004/48535
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KIST Publication > Conference Paper
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