Possible surface plasmon polariton excitation under femtosecond laser irradiation of silicon

The mechanisms of ripple formation on silicon surface by femtosecond laser pulses are investigated. We demonstrate the transient evolution of the density of the excited free-carriers. As a result, the experimental conditions required for the excitation of surface plasmon polaritons are revealed. The periods of the resulting structures are then investigated as a function of laser parameters, such as the angle of incidence, laser fluence, and polarization. The obtained dependencies provide a way of better control over the properties of the periodic structures induced by femtosecond laser on the surface of a semiconductor material.Comment: 11 pages, 8 figures, accepted for publication in Journal of Applied Physic

Nanofabrication with Pulsed Lasers

An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3), is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser–matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics

Closed-loop control of product properties in metal forming

Metal forming processes operate in conditions of uncertainty due to parameter variation and imperfect understanding. This uncertainty leads to a degradation of product properties from customer specifications, which can be reduced by the use of closed-loop control. A framework of analysis is presented for understanding closed-loop control in metal forming, allowing an assessment of current and future developments in actuators, sensors and models. This leads to a survey of current and emerging applications across a broad spectrum of metal forming processes, and a discussion of likely developments.Engineering and Physical Sciences Research Council (Grant ID: EP/K018108/1)This is the final version of the article. It first appeared from Elsevier via https://doi.org/10.1016/j.cirp.2016.06.00

Dopage laser en microélectronique

Les procédés de recuit et de dopage laser du silicium ont été étudiés de manière intensive au cours des précédentes décennies. Ces études ont d'ores et déjà permis un transfert technologique pour la fabrication des semiconducteurs. Cependant les futures générations CMOS vont nécessiter des techniques de dopage encore plus fines, capable de fabriquer les jonctions ultra-minces décrites dans la “roadmap” de l'ITRS (International Technology Roadmap for Semiconductors). Ce papier décrit des résultats récents obtenus dans le cadre du RMNT DOLAMI consacré au dopage laser de jonctions ultra-minces, ainsi que des applications du dopage laser pour les microtechnologies liées à la fabrication de MEMS

Modification of metals by high energy excimer laser

No abstract availabl

Detection of Lead and Arsenic Soil Pollution in Abandoned Industrial Poles to the South of Marseille, France by Laser-Induced Breakdown Spectroscopy

International audienceWe report on lead and arsenic soil pollution in abandoned industrial poles to the southof Marseille, France, where several lead production plants were active until the 1920's. Sincethis area is currently considered as building plot for residential districts, the detection of soilpollution is of great public interest. Here, a number of samples were collected andsubsequently investigated by calibration-free laser-induced breakdown spectroscopy. It wasshown that the concentration of both lead and arsenic within the collected samples isdrastically elevated in comparison to the particular natural content as reported in literature.Since the applied method does not require any standards for calibration, it is easy to use inorder to determine local soil pollution as a basis for soil clean up procedures

Laser-induced forward transfer for improving fine-line metallization in photovoltaic applications

International audienceGrand challenges to create new front metallization techniques in photovoltaic focus considerable attention on laser-induced forward transfer (LIFT) approach. This alternative method aims to overcome the limitations of the well-established and mature screen-printing (SP) technique. Such limitations are for instance restrictions in the grid pattern design, high-temperature steps, and limited aspect ratio of the line contact (Poulain et al. in Appl Surf Sci 257: 5241-5244, 2011). Although different new front contact metallization concepts have been studied, most of them require a second print step to increase the volume of the contact (Gao et al. in Proceedings of 25th EU PVSEC conference, 2010; Beaucarne and Schubert in Energy Proc 67: 2-12, 2015; Lossen and Matusovsky in Energy Proc 67: 156-162, 2015; Green in Phys E 14: 65-70, 2002; Lennon et al. in Prog Photovolt Res Appl V21: 1454-1468, 2012). As a result, it is desirable to find innovative metallization techniques to improve the cell efficiency without significantly increasing the cost. Although many challenges remain before to obtain high-quality, robust, and high-performance LIFT contact formation, it required a fully theoretical and experimental assessment. This paper presents the results of a study of the LIFT technique in picosecond regime and thick silver pastes to create high-quality conductive lines for photovoltaic applications

Formation of femtosecond laser induced surface structures on silicon: Insights from numerical modeling and single pulse experiments

International audienceLaser induced periodic surface structures (LIPSS) are formed by multiple irradiation of femtosecond laser on a silicon target. In this paper, we focus and discuss the surface plasmon polariton mechanism by an analysis of transient phase-matching conditions in Si on the basis of a single pulse experiment and numerical simulations. Two regimes of ripple formation mechanisms at low number of shots are identified and detailed. Correlation of numerical and experimental results is good. (c) 2011 Elsevier B.V. All rights reserved