0000000000745342
AUTHOR
Lucia Sládková
Detection of fluorine using laser-induced breakdown spectroscopy and Raman spectroscopy
In general, the detection of F and other halogens is challenging through conventional techniques. In this paper, various approaches for the qualitative and quantitative analysis of F using the laser-induced breakdown spectroscopy (LIBS) technique were demonstrated. In LIBS, fluorine detection can be realized by means of atomic lines and molecular bands. For the purposes of our experiment, two sets of pellets with various contents of CaF2, CaCO3 and cellulose were analyzed using a lab-based LIBS system under a He atmosphere. The fluorine atomic line at 685.60 nm was correlated with CaF signals proving their close relationship. Consequently, the limits of detection were determined for both an…
From Seeds to Islands: Growth of Oxidized Graphene by Two-Photon Oxidation
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. Sha…
From Seeds to Islands: Growth of Oxidized Graphene by Two-Photon Oxidation
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. Sha…