Alkali doping of graphene: the crucial role of high temperature annealing

The doping efficiency of lithium deposited at cryogenic temperatures on epitaxial and CVD monolayer graphene has been investigated under ultra-high vacuum conditions. Change of charge carrier density was monitored by gate voltage shift of the Dirac point and by Hall measurements, in low and high dop...

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Bibliographic Details
Published inarXiv.org
Main Authors Khademi, Ali, Sajadi, Ebrahim, Pinder Dosanjh, Bonn, Doug, Folk, Joshua A, Stöhr, Alexander, ti, Stiven, Starke, Ulrich
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 02.10.2016
Subjects
Annealing
Carrier density
Charge density
Cryogenic temperature
Current carriers
Doping
Graphene
High temperature
High vacuum
Lithium
Physics - Mesoscale and Nanoscale Physics
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Summary:The doping efficiency of lithium deposited at cryogenic temperatures on epitaxial and CVD monolayer graphene has been investigated under ultra-high vacuum conditions. Change of charge carrier density was monitored by gate voltage shift of the Dirac point and by Hall measurements, in low and high doping regimes. It was found that pre-annealing the graphene greatly enhanced the maximum levels of doping that could be achieved: doping saturated at \(\Delta n = 2\times 10^{13}\) e\(^-\)/cm\(^2\) without annealing, independent of sample type or previous processing; after a 900 K anneal, the saturated doping rose one order of magnitude to \(\Delta n = 2\times 10^{14}\) e\(^-\)/cm\(^2\).
ISSN:2331-8422
DOI:10.48550/arxiv.1610.00301