| AVS 61st International Symposium & Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS+2D-WeA |
| Session: | Plasma Processing for 2D Materials, Coating, and Surface Modification |
| Presenter: | Maria Antoaneta Bratescu, Aichi Science and Technology Foundation, Nagoya University, Japan |
| Authors: | M.A. Bratescu, Aichi Science and Technology Foundation, Nagoya University, Japan T. Ueno, Nagoya University, Japan N. Saito, Nagoya University, Japan |
| Correspondent: | Click to Email |
In order to be used in electronics and optics, graphene must be in contact with other materials, which can change its electrical and optical properties. The substrate, charge impurities, doping with chemical functional groups, and metal contacts can shift the position of the Fermi level of graphene. Furthermore, graphene with plasmonic nanoparticles (NPs) can offer a new perspective for light conversion systems, by optimization of visible light absorption via the SPR of the NPs, followed by electron exchange between graphene and NPs and electron transport through graphene.
In this work we present a facile, one-step, and surfactant-free method for the synthesis and loading of stable gold and gold-alloy NP on large-area graphene without NP deterioration using an electrical discharge in a liquid solution, termed solution plasma (SP). We investigated the charge transfer process between graphene and gold-alloy NPs by Raman spectroscopy and electron energy loss spectroscopy (EELS) in high resolution transmission electron microscopy (HRTEM).
The excess charge on graphene caused by transferred electrons or holes from the NPs to graphene was calculated from the change of the Fermi level relative to the initial position and the shift of the G band. In the case of graphene with gold NPs a decrease of the surface charge concentration with -3.5×1012 cm-2, and a movement of Fermi level with -0.06 eV.
In the case of the AuIn and AuGa NPs the transfer of electrons from graphene to the gold-alloy NPs produces an increase of the surface charge with 1.3×1012 cm-2 and 1.9×1012 cm-2, which correspond to a raising of Fermi level with 0.02 eV and 0.03 eV, respectively.
The EELS results were consistent with Raman spectroscopy results, i.e. the electrons and holes are transferred from the gold and gold-alloy NPs to graphene, respectively.
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M.A. Bratescu, et al., J. Alloys and Compounds 562 (2013) 74
M.A. Bratescu, et al., J. Phys. Chem. C 117 (2013) 26804