AVS 50th International Symposium
    Advanced Surface Engineering Tuesday Sessions
       Session SE-TuM

Paper SE-TuM3
Fabrication of Nanostructured Metallic Thin Films by Femtosecond Pulsed Laser Ablation

Tuesday, November 4, 2003, 9:00 am, Room 323

Session: Nanostructured, Nanocomposite, and Functionally Gradient Coatings
Presenter: M. Jaime Vasquez, State University of New York at Stony Brook
Authors: M. Jaime Vasquez, State University of New York at Stony Brook
T. Fiero, State University of New York at Stony Brook
G.P. Halada, State University of New York at Stony Brook
C.R. Clayton, State University of New York at Stony Brook
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Pulsed laser ablation is a well-known technique used for deposition of a variety of thin films for various applications. A major disadvantage of the use of excimer lasers has been the deposition of irregular melted droplets on the deposited film attributed to heterogeneities of the target, fluctuations in the laser fluence and other difficulties of process control. The extremely short pulse duration of femtosecond lasers results in reduction or complete prevention of lateral thermal damage as well as lower and more precise threshold fluences of ablation. This presentation focuses on both the mechanism of material ablation using femtosecond lasers as well as a number of examples of nanostructured metallic films of significance to analytical surface studies and catalysis. The femtosecond laser deposition process involves a high intensity laser pulse (10@super -15@ s range) that passes through an optical window of a vacuum chamber (10@super -6@ torr) and is focused onto the target, which can be a single metal, a mix of powders or a reactively arc melted coin. The partially ionized ejected material or ablation plume is then allowed to settle and form a thin film on a Si substrate. The plume itself was studied through analysis of the kinetics of ejected material from a Pt target and through charge screening methods to aid in determination of ionic character. In addition to Pt films, a nanostructured Al@sub 2@CuMg intermetallic thin film was formed (to study corrosion issues in Al aerospace alloys). Films were characterized by Secondary Electron Microscopy (SEM), Energy Dispersive Analysis of X-rays (EDAX), X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). Thin films were polyscrystalline and of the same composition as targets and chemically homogeneous. Observations of the morphological and structural features of the ablated films indicate that the technique can be used to reliably create nanostructured thin films.