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Ablation laser femtoseconde pour le dépôt de couches minces

Abstract : This research report concern the elaboration of thin films by femtosecond Pulsed laser deposition (PLD) and the characterization of the plasma plume. An overview of the results obtained on pure Diamond-Like Carbon (DLC) thin films are presented with the goal of depositing films with high hardness and low friction and wear coefficients, with good adhesive properties on various biomedical substrates, including stainless steel or polyethylene. Thin films have been successfully deposited on the femoral head of hip joints. The properties of DLC films elaborated by femtosecond and nanosecond PLD are compared through the optical properties of the films and the properties of the laser-induced plasma plume.
Nanoparticles have been also deposited by femtosecond PLD and included in an amorphous matrix of DLC. By this way, we deposited metal-doped DLC films with tantalum or nickel due to their different chemical affinity with respect to carbon. Two different crystalline phases are obtained in the case of the tantalum-doped DLC film, with the surprising presence of a metastable β-Ta phase, which is correlated to the properties of the plasma plume. Tantalum carbide is also evidenced in a thin layer at the edge of the tantalum clusters.
Pure DLC and metal-doped DLC films have been investigated in the frame of electrodes for biosensors. The possibility of using such materials with high sensitivity and low detection limits is shown. The optimization through the incorporation of an other dopant (boron) is dicussed.
The possibility of using such boron-doped DLC films for thermal and nanocalorimetric sensors in investigated through another ANR support framework. The DLC thermometers with high TCR coefficient (Temperature Coefficient of Resistance) are integrated in suspended isolated structures and show already suitable properties,
In the last part of this research report, propects of our works are presented through the temporal shaping of the laser beam. The outcome has potential interest for thin films elaboration or nanoparticles synthesis. Indeed, a possible way to achieve higher film quality and better control of the ablation process is to regulate the interaction process via spatio-temporal modification of the laser beam. We have developped an experimental tool allowing the possibility of tailoring the plasma plume by adaptive temporal shaping. Preliminary results on the use of an adaptive feedback optimization procedure that adjust the laser temporal form for modulating plasma optical properties are presented. This work is focused on the enhancement of the ionic emission with respect to the neutral emission lines of the plasma induced by laser irradiation of an aluminum sample. Such an optimization leads to plasma plume properties rather different from conventional femtosecond pulses (such as double or long pulses) and to films with lower density of nanoparticles, which is promising for future works.
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Contributor : Florence Garrelie <>
Submitted on : Tuesday, January 27, 2009 - 11:25:26 AM
Last modification on : Monday, January 13, 2020 - 5:46:02 PM
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  • HAL Id : tel-00356315, version 1

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Florence Garrelie. Ablation laser femtoseconde pour le dépôt de couches minces. Physique [physics]. Université Jean Monnet - Saint-Etienne, 2008. ⟨tel-00356315⟩

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