IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Organic Films and Devices Wednesday Sessions
       Session OF+TF+EL-WeA

Paper OF+TF+EL-WeA2
Resonant Mid-Infrared Pulsed Laser Deposition of Polymer Films

Wednesday, October 31, 2001, 2:20 pm, Room 131

Session: Growth of Organic Thin Films
Presenter: R.F. Haglund, Vanderbilt University
Authors: R.F. Haglund, Vanderbilt University
M.R. Papantonakis, Vanderbilt University
D.M. Bubb, Naval Research Laboratory
J.S. Horwitz, Naval Research Laboratory
J.S. Callahan, Naval Research Laboratory
R.A. McGill, Naval Research Laboratory
E.J. Houser, Naval Research Laboratory
D.B. Chrisey, Naval Research Laboratory
M. Galicia, George Washington University
A. Vertes, George Washington University
B. Toftmann, Risoe National Laboratory, Denmark
Correspondent: Click to Email
Resonant, picosecond-pulse, mid-infrared laser irradiation has been shown to ablate glassy and crystalline solids with high efficiency and low collateral damage.@footnote 1@ We have extended this concept to show that resonant infrared (IR) pulsed-laser deposition (PLD) is an effective method for depositing polymer films with physical and chemical structure as well as optical properties virtually identical to those of the bulk starting material. This contrasts sharply with PLD at ultraviolet (UV) wavelengths, where deposited polymer material is sometimes significantly degraded. In our experiments, the organic starting material was ablated by a pulsed infrared, free electron laser tuned into resonance with various vibrational modes; the vapor was collected on a room-temperature substrate. For polyethylene glycol (PEG, MW 1450) the laser was tuned to either C-H or O-H stretching modes at 2.9 and 3.4 µm, respectively. The properties of the deposited film were determined using infrared absorption spectroscopy and mass spectrometry. When the infrared laser was detuned from resonance, the structure and optical properties of the deposited PEG film were significantly altered, showing that the off-resonance ablation process thermally damages the polymer. The potential for generalizing this technique can be seen in the successful deposition of poly(lactide co-glocolide) (PLCA, MW 67,000). PLCA films were deposited using 5.7 µm excitation (1754 cm@super-1@), where the laser excitation is localized by the C=O stretch. The mechanism of ablation appears to be explosive vaporization; in contrast to the photochemical mechanism typical of UV ablation, the ablated material seems to remain in the electronic ground state. The technique appears promising for biomedical and electronic applications of polymeric and organic thin films. @FootnoteText@ @footnote 1@ D. R. Ermer, M. R. Papantonakis, M. Baltz-Knorr, D. Nakazawa and R. F. Haglund, Jr., Appl. Phys. A 70, 633-635 (2000).