Picosecond and femtosecond pulsed laser ablation and deposition of quasicrystals

• Published in: Applied surface science Vol. 210; no. 3; pp. 307 - 317
• Main Authors: Teghil, R, D’Alessio, L, Santagata, A, Zaccagnino, M, Ferro, D, Sordelet, D.J
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.04.2003; Elsevier Science
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Laser ablation; Laser-plasma interactions; Metals. Metallurgy; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Quasicrystals; Semi-periodic solids; Structure and morphology; thickness; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Ultrashort laser pulses; 81.15.Fg; Laser ablation; 52.38.Mf; Quasicrystals; Ultrashort laser pulses; 61.44.Br; Atomic force microscopy; Laser-produced plasma; Ternary alloys; Iron alloys; 52.38.Mf Laser ablation: Quasicrystals: Ultrashort laser pulses; XRD; Pulsed lasers; Surface structure; Thin films; Picosecond; Emission spectra; Imaging; Plasma characteristic; Femtosecond; Scanning electron microscopy; Aluminium base alloys; X-ray spectra; Dispersive spectrometry; Surface composition; Film growth; Surface melting; Copper alloys; Laser ablation technique; Mass spectra
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/S0169-4332(03)00082-5

A Nd:glass laser with pulse duration of 250 fs and 1.3 ps has been used to evaporate a Al 65Cu 23Fe 12 quasicrystalline target. The gaseous phase obtained from the ablation process has been characterised by several techniques such as emission spectroscopy, quadrupole mass spectrometry and ICCD imaging, used to study the plume composition, energy and morphology. The results show that the ablation processes in the short-pulse regimes are very different to the nanosecond one. In particular the plume angular distribution shows a characteristic high cosine exponent and the composition is completely stoichiometric and independent from the laser fluence. Furthermore the mass spectra indicate the presence of clusters, both neutral and ionised and the emission from the target suggest a rapid thermalisation leading to the melting of the surface. To clarify the ablation process some films have been deposited, on oriented silicon, at different experimental conditions and analysed by scanning electron microscopy, atomic force microscopy, energy dispersive X-ray analysis and X-ray diffraction. The analyses show the presence of nanostructured films retaining the target stoichiometry but consisting of different crystalline and non crystalline phases. In particular the nanostructure supports the hypothesis of the melting of the target during the ablation and a mechanism of material ejection is proposed for both picosecond and femtosecond regimes.