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Master's Dissertation
DOI
https://doi.org/10.11606/D.76.2020.tde-11052020-134154
Document
Author
Full name
Flavio Pinto de Almeida Filho
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2019
Supervisor
Committee
Mendonça, Cleber Renato (President)
Ferreira, Paulo Henrique Dias
Gonçalves, Rogéria Rocha
Title in Portuguese
Processamento com laser de femtossegundos em diamond-like carbon
Keywords in Portuguese
Diamond like carbon
Incubação
Microfabricação
Abstract in Portuguese
Neste trabalho investigamos o processo de estruturação em filmes de Diamond-like Carbon (DLC) através do uso de pulsos laser de femtossegundos (100 fs, 800 nm, 1 KHz e 5 MHz). Determinamos a fluência de limiar para estruturação do DLC como sendo da ordem de 1 J/cm2 para pulso único e de aproximadamente 0,1 J/cm2 quando a amostra é submetida a um grande número de pulsos (> 104 pulsos). Por meio da espectroscopia Raman determinamos as intensidades de pico das bandas D e G, características do DLC, e a partir da sua razão foi possível estimar uma fração de hibridações sp3 na amostra de 70 %. Identificamos ainda a ocorrência do processo de grafitização nas regiões onde houve a irradiação laser. Finalmente, foi possível também observar a formação de pequenas estruturas assimétricas, com diâmetro médio de 1,5 μm e espaçamento de 3 μm, geradas por uma fluência de 0,13 J/cm2. Por meio da espectroscopia de raio X por dispersão (EDS), concluímos que tais estruturas são geradas pelo processo de fusão do substrato facilitada pela interação da luz com o filme de DLC.
Title in English
Femtosecond laser processing of diamond-like carbon
Keywords in English
Diamond like carbon
Incubation
Micromachine
Abstract in English
In this work we investigate the structuring process in Diamond-like Carbon (DLC) films through the use of femtosecond laser pulses (100 fs, 800 nm, 1 KHz and 5 MHz). We determined the threshold fluence for structuring DLC to be in the order of 1 J/cm2 for a single pulse and approximately 0.1 J/cm2 when the sample is subjected to a large number of pulses (> 104 pulses). Raman spectroscopy determined the peak intensities of the D and G bands, characteristic of the DLC, and from its ratio it was possible to estimate a fraction of sp3 hybridizations in the sample of 70%. We also identified the occurrence of the graphitization process in the regions where there was laser irradiation. Finally, it was also possible to observe the formation of small asymmetric structures, with an average diameter of 1.5 μm and spacing of 3 μm, generated by a fluency of 0.13 J / cm2. Through X-ray scattering spectroscopy (EDS), we conclude that such structures are generated by the substrate fusion process facilitated by the interaction of light with the DLC film.
 
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Publishing Date
2020-05-13
 
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