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RESEARCH PRODUCT
From Seeds to Islands: Growth of Oxidized Graphene by Two-Photon Oxidation
Juha KoivistoinenKevin RobertsAndreas JohanssonPekka KoskinenMika PetterssonJukka AumanenPasi MyllyperkiöLucia SládkováLucia Sládkovásubject
Materials scienceoxidationAnalytical chemistry02 engineering and technology010402 general chemistryPhotochemistry01 natural scienceslaw.inventionsymbols.namesakeTwo-photon excitation microscopylawPhenomenological modelIrradiationPhysical and Theoretical Chemistryta116Coalescence (physics)patterningta114Graphenegraphene021001 nanoscience & nanotechnology0104 chemical sciencesSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsGeneral EnergyHomogeneousFemtosecondsymbols0210 nano-technologyRaman spectroscopydescription
The mechanism of two-photon induced oxidation of single-layer graphene on Si/SiO2 substrates is studied by atomic force microscopy (AFM) and Raman microspectroscopy and imaging. AFM imaging of areas oxidized by using a tightly focused femtosecond laser beam shows that oxidation is not homogeneous but oxidized and nonoxidized graphene segregate into separate domains over the whole irradiated area. The oxidation process starts from point-like “seeds” which grow into islands finally coalescing together. The size of islands before coalescence is 30–40 nm, and the density of the islands is on the order of 1011 cm–2. Raman spectroscopy reveals growth of the D/G band ratio along the oxidation. Sharpness of the D-band which persists over a large range of oxidation and the maximal value of the intensity ratio of the D- and G-bands (∼0.8) indicates that graphene oxidation proceeds by an increase of the oxidized area rather than progression of oxidized areas to fully disordered structure. A phenomenological model is...
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-09-20 | The Journal of Physical Chemistry C |