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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:30 |
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Conference: Bucharest University Faculty of Physics 2013 Meeting
Section: Optics, Spectroscopy, Plasma and Lasers
Title:
Periodical structures induced by femtosecond laser on silicon in air
Authors:
C. Albu and M. Zamfirescu
Affiliation:
National Institute for Laser, Plasma and Radiation Physics, Atomistilor 409, 077125 Magurele, Romania
E-mail
catalina.radu@inflpr.ro
Keywords:
femtosecond laser, silicon, LIPSS
Abstract:
In the paste decade, texturing semiconductors with ultrashort pulsed lasers has received considerable attention due to its important technological applications for photovoltaics, microelectronics or microbiology products. Ripples or laser-induced periodic surface structures (LIPSS) have been observed near the ablation threshold of materials since the beginning of laser processing of materials. For these structures, different formation mechanisms were proposed such as self-organization, the second harmonic generation (SHG) or excitation of surface plasmons (SPs). Nevertheless, none of these models can give a complete explanation of LIPSS formation, and their formation mechanism still remains under debate.In our experiments, nanostructured surfaces were obtained on silicon target by irradiation with single femtosecond laser pulse in air. The silicon samples was processed by linearly polarised Ti:Sapphire laser, at repetition rate of 2 kHz, pulse duration of 200 fs, and 775 nm wavelengths. The morphological changes and characterization of the laser-modified surface was studied by Optical Microscopy (OM) and Atomic Force Microscopy (AFM). Depending on the irradiation conditions, such as laser fluence or angle of incidence, different morphology has been obtained: concentric wave or ripples perpendicular to the laser polarization. The interference of the incident laser beam with the surface plasmon-polariton wave excited on the target surface is proposed to explain the formation mechanisms of the periodic ripples.
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