Emc 2016 Confirmation of abstract submission

EMC 2016 - Confirmation of abstract submission

Dear Colleague,
This email confirms submission of the following abstract for the EMC 2016 congress. This abstract was submitted on the 29/03/2016 15:18.

This abstract may be edited until the deadline, however you MUST re-submit the abstract in order for any changes to be considered.

Below please find the information you have submitted for this abstract.

Submission details

ID number #6518

This ID must be used in all correspondence about this abstract.

Title: Temperature rise during laser-induced self-organization of nanoparticle gratings revealed by Raman microspectroscopy and electron microscopy

Keywords : nanoparticles, films, laser, growth, self-organization

Presenter:

• Zeming Liu (Univ Lyon, UJM‐Saint‐Etienne, CNRS, Institut d'Optique Graduate School, Laboratoire Hubert Curien UMR 5516, F‐42023 - Saint-Etienne - FRANCE)

Co-author(s):

• Guy Vitrant (IMEP-LAHC, Minatec, Grenoble-INP, CNRS-UMR 5130, F-38016 - grenoble - FRANCE)

• Lucien Saviot (Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303, CNRS-Université de Bourgogne, F-21078 - Dijon - FRANCE)

• Maria-Del-Carmen Marco-De-Lucas (Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303, CNRS-Université de Bourgogne, F-21078 - Dijon - FRANCE)

• Thierry Epicier (MATEIS, umr CNRS 5510, University of Lyon, INSA Lyon, University Lyon I - Villeurbanne - FRANCE)

• Matthieu Bugnet (MATEIS, umr CNRS 5510, University of Lyon, INSA Lyon, University Lyon I - Villeurbanne - FRANCE)

• Yaya Lefkir (Univ Lyon, UJM‐Saint‐Etienne, CNRS, Institut d'Optique Graduate School, Laboratoire Hubert Curien UMR 5516, F‐42023 - Saint-Etienne - FRANCE)

• Stéphanie Reynaud (Univ Lyon, UJM‐Saint‐Etienne, CNRS, Institut d'Optique Graduate School, Laboratoire Hubert Curien UMR 5516, F‐42023 - Saint-Etienne - FRANCE)

• Jan Siegel (Laser Processing Group, Instituto de Optica, Serrano 121, 28006 - Madrid - SPAIN)

• Mario Garcia-Lechuga (Laser Processing Group, Instituto de Optica, Serrano 121, 28006 - Madrid - SPAIN)

• Javier Solis (Laser Processing Group, Instituto de Optica, Serrano 121, 28006 - Madrid - SPAIN)

• Nathalie Destouches (Univ Lyon, UJM‐Saint‐Etienne, CNRS, Institut d'Optique Graduate School, Laboratoire Hubert Curien UMR 5516, F‐42023 - Saint-Etienne - FRANCE)

Topic: MS4: Complex materials

Preferred format: Oral presentation

Your abstract:

Self-organization of metallic nanoparticles (NPs) has recently been reported upon visible continuous-wave (cw) laser exposure [1]. The self-organized structures are Ag NP gratings embedded in a thin TiO₂ film deposited on glass. Such composite structures exhibit singular visual effects that can find applications in secured traceability. The related optical properties directly depend on the NP size distribution, the average grating period, the organization rate and the TiO₂ thickness and refractive index. These sample features appear to be largely controlled by the temperature rise that occurs during the laser-induced self-organization process. In this contribution, we estimate the plasmon-induced temperature rise and we show that it is strongly influenced by the laser scanning speed. In complement, various modes of transmission electron microscopy (TEM) are used to get accurate information on the NP size distributions resulting from different temper ature rises, on their localization in the film and on the phase and chemical changes that occur in the film and the substrate surrounding NPs. Finally, we show how such thermal effects can be considerably decreased when using femtosecond (fs) laser pulses to initiate the NP self-organization.

The TiO₂ thin layer used in this work is initially mesoporous and amorphous and contains small silver NP of 1-3 nm as described in a previously published article [1]. The self-organized growth of silver NPs is implemented by scanning a laser beam focused on the sample surface at a constant speed. Post mortem Raman microspectroscopy characterizations allow to identify different scanning speed ranges where TiO₂ remains amorphous, crystallizes into the anatase phase, in both anatase and rutile phases or only in the rutile phase, as confirmed by high resolution TEM micrographs. These results tend to show that the temperature rise during exposure increases when the scanning speed increases, which was totally unexpected. In situ Raman microspectroscopy measurements then attest an increase in temperature from 200°C to 750°C from low speed to higher speed in a range where anatase is formed. Scanning electron microscopy (SEM) is then quit e useful, to identify different morphologies for anatase and rutile nanocrystals and to study changes in the nanocrystal density as a function of speed.

Scanning TEM (STEM) micrographs and electron energy loss spectroscopy (EELS) analysis of sample cross-sections prepared by focused ion beam (FIB) give interesting additional information about the in-depth structure of samples. Ag nanoparticles are located below the TiO₂ film (Fig. 1a) made of TiO₂ nanocrystals immersed in a Si-based amorphous phase, in a new thin amorphous layer including both Ti from the initial film and Si from the glass substrate (Fig. 1b). A three-dimensional reconstruction of the film sample from a series of FIB-SEM experiments confirms that all Ag NPs are rather spherical and located in a single plane just below the nanocrystalized TiO₂ layer. Non-monotonous changes in the NP size distribution with the temperature rise are further investigated by the analysis of high angle annular dark field scanning TEM (HAADF STEM) micrographs for many samples.

Finally, to investigate a way to self-organize metallic NPs without high temperature rise in order to preserve the substrate and give the ability to work on soft substrates like plastic ones, we present few results obtained with fs laser pulses. They give rise to self-organization without altering the substrate top surface (Fig. 1 c-d). Ag NPs remain localized in the TiO₂ films, which is only locally crystalized around the grown NPs, as attested by STEM-diffraction maps recorded in TEM.

To conclude, this paper proposes a thorough study of the 3D nanostructure and chemical composition of complex samples made of Ag NP gratings embedded in a nanocrystalized TiO₂ film, which result from laser-induced self-organization processes. It provides crucial information on thermal effects that drive the self-organization process and that occur in very short times.