Real-time monitoring of graphene patterning with wide-field four-wave mixing microscopy

Koivistoinen, Juha; Aumanen, Jukka; Hiltunen, Vesa-Matti; Myllyperkiö, Pasi; Johansson, Andreas; Pettersson, Mika

doi:10.1063/1.4946854

Cited by 9 publications

(13 citation statements)

References 23 publications

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“…When used for imaging, all FWM signals corresponding to various processes are collected via microscope objective and directed to a detector, yielding strong signal intensity corresponding to large third-order nonlinear response of graphene. 10 Whereas this approach results in high image contrast and low noise level, the trade-off is information loss of the different nonlinear processes and dynamics because the FWM signals arising from separate processes are mixed. Different FWM signals can be separated spatially by using BOXCARS excitation geometry.…”

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confidence: 99%

Time-Resolved Coherent Anti-Stokes Raman Scattering of Graphene: Dephasing Dynamics of Optical Phonon

Koivistoinen

Myllyperkiö

Pettersson

2017

J. Phys. Chem. Lett.

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We report dynamics of the G-mode in graphene probed with time-resolved coherent anti-Stokes Raman scattering measurements. By applying BOXCARS excitation geometry with three different excitation wavelengths, various nonlinear processes can be selectively detected due to energy and momentum conservation and temporal sequence of the pulses. The Raman signal due to resonant coherent excitation of the G-mode shows exponential decay with lifetime of ∼325 ± 50 fs. This decay time is shorter than expected based on the line width of the G-mode in the Raman spectrum. We propose that the unexpectedly short dephasing time is a result of dynamic variation of nonadiabatic coupling of the photoexcited electron distribution and the G-mode.

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confidence: 99%

Time-Resolved Coherent Anti-Stokes Raman Scattering of Graphene: Dephasing Dynamics of Optical Phonon

Koivistoinen

Myllyperkiö

Pettersson

2017

J. Phys. Chem. Lett.

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“…Recently, we presented an opposite approach by performing laser-induced oxidation of graphene with a two-photon mechanism using short femtosecond pulses. 9,10 Opening of a band gap in graphene was demonstrated as a result of oxidation, which could be controlled by adjusting irradiation parameters. This observation is in agreement with several studies which show that the band gap of GO depends on the level of oxidation.…”

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From Seeds to Islands: Growth of Oxidized Graphene by Two-Photon Oxidation

et al. 2016

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ABSTRACT. Mechanism of two-photon induced oxidation of single-layer graphene on Si/SiO 2 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 non-oxidized graphene segregate into separate domains over the whole irradiated area. Oxidation process starts from point-like "seeds" 2 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 10 11 cm -2 . Raman spectroscopy reveals growth of the D/G band ratio along the oxidation. Sharpness of the D-band which persists over 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 increase of the oxidized area rather than progression of oxidized areas to fully disordered structure. A phenomenological model is developed which explains the observations. According to the model, the probability for oxidation of a site next to already oxidized site is five orders of magnitude higher than oxidation of pristine graphene. Irradiation of an extended area by raster scanning leads to a formation of an irregular nanomesh of oxide islands with a narrow size distribution. The phenomenological model yields similar results as the experiment. This study forms a basis for controlled use of two-photon oxidation for tailoring properties of graphene and patterning it with sub-micrometer resolution.

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“…( b ) Time-varying image of the FWM signal of photo-oxidation graphene, where yellow is the oxidized laser beam and white is the FWM signal. Reproduced from [ 100 ], with permission from AIP Publishing, 2016.…”

Section: Figurementioning

confidence: 99%

“…For the photo-oxidation of graphene, a wide-field FWM microscope can be used to monitor the GO pattern in real time (Figure 12b), and the changes caused by photo-oxidation are displayed as dark areas in the FWM image. Compared to commonly used Raman imaging, this method provides a sensitive, non-destructive way for the rapid large-area characterization of graphene [100]. can be used to monitor the GO pattern in real time (Figure 12b), and the changes caused by photo-oxidation are displayed as dark areas in the FWM image.…”

Section: Chemical Dynamicsmentioning

confidence: 99%

“…can be used to monitor the GO pattern in real time (Figure 12b), and the changes caused by photo-oxidation are displayed as dark areas in the FWM image. Compared to commonly used Raman imaging, this method provides a sensitive, non-destructive way for the rapid large-area characterization of graphene [100]. Different nonlinear detection methods have different responses to the chemical kinetic detection of 2D materials.…”

Section: Chemical Dynamicsmentioning

confidence: 99%

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Nonlinear Optical Characterization of 2D Materials

Zhou

Wang

et al. 2020

Nanomaterials

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Characterizing the physical and chemical properties of two-dimensional (2D) materials is of great significance for performance analysis and functional device applications. As a powerful characterization method, nonlinear optics (NLO) spectroscopy has been widely used in the characterization of 2D materials. Here, we summarize the research progress of NLO in 2D materials characterization. First, we introduce the principles of NLO and common detection methods. Second, we introduce the recent research progress on the NLO characterization of several important properties of 2D materials, including the number of layers, crystal orientation, crystal phase, defects, chemical specificity, strain, chemical dynamics, and ultrafast dynamics of excitons and phonons, aiming to provide a comprehensive review on laser-based characterization for exploring 2D material properties. Finally, the future development trends, challenges of advanced equipment construction, and issues of signal modulation are discussed. In particular, we also discuss the machine learning and stimulated Raman scattering (SRS) technologies which are expected to provide promising opportunities for 2D material characterization.

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Real-time monitoring of graphene patterning with wide-field four-wave mixing microscopy

Cited by 9 publications

References 23 publications

Time-Resolved Coherent Anti-Stokes Raman Scattering of Graphene: Dephasing Dynamics of Optical Phonon

Time-Resolved Coherent Anti-Stokes Raman Scattering of Graphene: Dephasing Dynamics of Optical Phonon

From Seeds to Islands: Growth of Oxidized Graphene by Two-Photon Oxidation

Nonlinear Optical Characterization of 2D Materials

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