Geometrical magnetoresistance effect and mobility in graphene field-effect transistors

Isabel Harrysson Rodrigues*, Andrey Generalov, Miika Soikkeli, Anton Murros, Sanna Arpiainen, Andrei Vorobiev

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    3 Citations (Scopus)

    Abstract

    Further development of graphene field-effect transistors (GFETs) for high-frequency electronics requires accurate evaluation and study of the mobility of charge carriers in a specific device. Here, we demonstrate that the mobility in the GFETs can be directly characterized and studied using the geometrical magnetoresistance (gMR) effect. The method is free from limitations of other approaches since it does not require an assumption of the constant mobility and the knowledge of the gate capacitance. Studies of a few sets of GFETs in the wide range of transverse magnetic fields indicate that the gMR effect dominates up to approximately 0.55 T. In higher fields, the physical magnetoresistance effect starts to contribute. The advantages of the gMR approach allowed us to interpret the measured dependencies of mobility on the gate voltage, i.e., carrier concentration, and identify the corresponding scattering mechanisms. In particular, the range of the fairly constant mobility is associated with the dominating Coulomb scattering. The decrease in mobility at higher carrier concentrations is associated with the contribution of the phonon scattering. Analysis shows that the gMR mobility is typically 2-3 times higher than that found via the commonly used drain resistance model. The latter underestimates the mobility since it does not take the interfacial capacitance into account.

    Original languageEnglish
    Article number013502
    JournalApplied Physics Letters
    Volume121
    DOIs
    Publication statusPublished - 7 Jul 2022
    MoE publication typeA1 Journal article-refereed

    Funding

    This work was supported, in part, by the EU Graphene Flagship Core 3 Project under Grant No. 881603. This work was performed, in part, at Myfab Chalmers and, in part, at the Micronova Nanofabrication Centre. A.G. and S.A. acknowledge funding from the Academy of Finland (Grant Nos. 343842 and 314809), and A.M. and M.S. acknowledge funding from the Graphene Flagship 2D Experimental Pilot Line.

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