Periodic nanoripple generated by femtosecond laser beam in LCVD system

We demonstrate deposition of periodic tungsten nanoripple on different substrate using a single 400nm femtosecond laser beam at room temperature. The laser beam generated by frequency doubling the output from mode-locked 80MHz Ti: sapphire oscillator was applied in a laser-induced chemical vapor deposition configuration, in which tungsten hexacarbonyl was used as precursor. The deposition strongly depended on laser polarization. With linearly polarized light, periodic ripple structure with willow-leaf shape was formed inside the exposure area. The ripple orientation was found parallel to the laser polarization direction. Affects of laser power and exposure time on ripple formation were investigated. By translating the substrate with respective to the laser beam, longitudinal or transverse grating structure was observed. The period of this grating structure is about 150nm on sapphire, and the orientation is parallel to laser polarization. Simply by programming the translation of the substrate, large area patterns and other patterns such as circle and characters were formed. Similar ripple and grating structures observed on all the substrates we investigated, including insulators, semiconductors and metals, implies that ripple formation might be a universal phenomenon. Considering the simplicity of this process and material flexibility of laser CVD, this technique may provide a novel costeffective patterning method to produce periodic subwavelength nanostructures of a wide range of materials on many substrates.

[1]  E. Zemskov,et al.  Theory of the formation of "normal" and "anomalous" gratings on the surfaces of absorbing condensed media exposed to laser radiation , 1984 .

[2]  B N Chichkov,et al.  Femtosecond laser-induced two-photon polymerization of inorganic-organic hybrid materials for applications in photonics. , 2003, Optics letters.

[3]  R M Osgood,et al.  Optically induced microstructures in laser-photodeposited metal films. , 1982, Optics letters.

[4]  Philippe M. Fauchet,et al.  Stimulated Wood's anomalies on laser-illuminated surfaces , 1986 .

[5]  John E. Sipe,et al.  Laser Induced Periodic Surface Structure , 1982 .

[6]  A. Gaeta,et al.  Infrared photosensitivity in silica glasses exposed to femtosecond laser pulses. , 1999, Optics letters.

[7]  John E. Sipe,et al.  Laser-Induced Periodic Surface Structure on Solids: A Universal Phenomenon , 1982 .

[8]  Razvan Stoian,et al.  Laser ablation of dielectrics with temporally shaped femtosecond pulses , 2002 .

[9]  Dieter Bäuerle,et al.  Laser processing and chemistry: recent developments , 2002 .

[10]  Frances A. Houle,et al.  Photochemical deposition of thin films from the metal hexacarbonyls , 1990 .

[11]  Wilson,et al.  Composition, structure, and electric field variations in photodeposition. , 1985, Physical review letters.

[12]  Alfred Wagner,et al.  Metal deposition with femtosecond light pulses at atmospheric pressure , 2003 .

[13]  Daniel J. Ehrlich,et al.  Stimulated Surface-Plasma-Wave Scattering and Growth of a Periodic Structure in Laser-Photodeposited Metal Films , 1982 .

[14]  K. Miura,et al.  Writing waveguides in glass with a femtosecond laser. , 1996, Optics letters.