Probing low-density carriers in a single atomic layer using terahertz parallel-plate waveguides

dc.citation.journalTitleOptics Expressen_US
dc.contributor.authorRazanoelina, Manjakavahoakaen_US
dc.contributor.authorBagsican, Filchito Reneeen_US
dc.contributor.authorKawayama, Iwaoen_US
dc.contributor.authorZhang, Xiangen_US
dc.contributor.authorMa, Luluen_US
dc.contributor.authorMurakami, Hironaruen_US
dc.contributor.authorVajtai, Roberten_US
dc.contributor.authorAjayan, Pulickel M.en_US
dc.contributor.authorKono, Junichiroen_US
dc.contributor.authorTonouchi, Masayoshien_US
dc.description.abstractAs novel classes of two-dimensional (2D) materials and heterostructures continue to emerge at an increasing pace, methods are being sought for elucidating their electronic properties rapidly, non-destructively, and sensitively. Terahertz (THz) time-domain spectroscopy is a well-established method for characterizing charge carriers in a contactless fashion, but its sensitivity is limited, making it a challenge to study atomically thin materials, which often have low conductivities. Here, we employ THz parallel-plate waveguides to study monolayer graphene with low carrier densities. We demonstrate that a carrier density of ~2 × 1011 cm−2, which induces less than 1% absorption in conventional THz transmission spectroscopy, exhibits ~30% absorption in our waveguide geometry. The amount of absorption exponentially increases with both the sheet conductivity and the waveguide length. Therefore, the minimum detectable conductivity of this method sensitively increases by simply increasing the length of the waveguide along which the THz wave propagates. In turn, enabling the detection of low-conductivity carriers in a straightforward, macroscopic configuration that is compatible with any standard time-domain THz spectroscopy setup. These results are promising for further studies of charge carriers in a diverse range of emerging 2D materials.en_US
dc.identifier.citationRazanoelina, Manjakavahoaka, Bagsican, Filchito Renee, Kawayama, Iwao, et al.. "Probing low-density carriers in a single atomic layer using terahertz parallel-plate waveguides." <i>Optics Express,</i> 24, no. 4 (2016) The Optical Society: 3885-3893.
dc.publisherThe Optical Society
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
dc.titleProbing low-density carriers in a single atomic layer using terahertz parallel-plate waveguidesen_US
dc.typeJournal articleen_US
dc.type.publicationpublisher versionen_US
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