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Molecular detection by liquid gated Hall effect measurement of graphene


Conventional electrical biosensing techniques include Cyclic Voltammetry (CV, amperometric) and ion-sensitive field effect transistor (ISFET, potentiometric). However, CV is not able to detect electrochemically inactive molecules where there is no redox reaction in solution, and the resistance change of pristine ISFETs in response to low concentration solutions is not observable. Here we show a very sensitive label-free biosensing method using Hall effect measurements on unfunctionalized graphene devices where the gate electrode is immersed in the solution containing the analyte of interest. This liquid gated Hall effect measurement (LGHM) technique is independent of redox reactions, and it enables extraction of additional information of electrical properties from graphene as compared with ISFETs, which can be used to improve the sensitivity. We demonstrate that LGHM has a higher sensitivity than conventional biosensing methods for L-histidine in the pM range. The detection mechanism is proposed to be based on the interaction between the ions and graphene. The ions could induce the asymmetry of the electron-hole mobility and the inhomogeneity in graphene, and they may also respond to the Hall measurement. Moreover, calculation of the capacitance values shows that the electrical double layer capacitance is dominant at relatively high gate voltages in our system, and this is useful for applications including biosensing, energy storage, and neural stimulation.

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Publication details

The article was received on 25 Aug 2017, accepted on 04 Dec 2017 and first published on 05 Dec 2017

Article type: Communication
DOI: 10.1039/C7NR06330J
Citation: Nanoscale, 2017, Accepted Manuscript
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    Molecular detection by liquid gated Hall effect measurement of graphene

    H. Zhan, J. Cervenka, S. Prawer and D. Garrett, Nanoscale, 2017, Accepted Manuscript , DOI: 10.1039/C7NR06330J

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