Ripple formation in the chromium thin film during laser ablation

• Published in: Applied surface science Vol. 253; no. 15; pp. 6584 - 6587
• Main Authors: Regelskis, Kęstutis, Račiukaitis, Gediminas, Gedvilas, Mindaugas
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 30.05.2007; Elsevier Science
• Subjects: Chromium on glass; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Gratings; Impact phenomena (including electron spectra and sputtering); Laser ablation; Laser-beam impact phenomena; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Pattern formation; Physics; Ripples; Theory and models of film growth; Thin films; Thin films; 42.62.Cf; Pattern formation; 89.20.Bb; Ripples; 47.20.Dr; Chromium on glass; 68.55.Ac; Laser ablation; Gratings; Line widths; Optical fiber networks; Film growth; Laser radiation; Transition elements; Chromium; Instability; Laser ablation technique; Liquid films; Pattem formation
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.01.048

The beam of a nanosecond pulse laser tightly focused to a line was applied for the back-side ablation of the chromium thin film on a glass substrate. The stripe ablated with a single laser pulse had sharp edges on both sides and ridges of the melted metal around it. The partially overlapping pulses formed a wide cleaned area with a complicated structure made of the metal remaining from the ridges. Regular structures, ripples, were developed when laser fluence was slightly above the single-pulse removal threshold and the shift between pulses was less than half width of the line ablated with a single laser pulse. The ripples were located periodically (∼4 μm) and were orientated perpendicularly to the long axis of the beam spot. Their orientation did not depend on the laser beam polarization. Different models of the ripple formation in the thin metal film were considered, and instability of the moving vapor–liquid–solid contact line during evaporation of thin liquid films appears to be the most probable process responsible for the observed phenomena. Formation of regular gratings with the unlimited line length was experimentally implemented by using the above-mentioned technique.