Femtosecond laser processing of indium-tin-oxide thin films

• Fabrication of micro- and nano-scale c-ITO patterns from a-ITO thin films by (NA 0.26) femtosecond laser pulses that are not tightly focused.
• Discontinuous c-ITO dot patterns with a diameter of ~1.4 µm were obtained.
• Two parallel c-ITO patterns with periodic-like glass nanostructures (350±15 nm) at a single laser written path were obtained.
• A smooth nano-scale c-ITO line pattern ~0.9 µm (about 1/8 smaller than the focused beam׳s diameter) was obtained.

Micro- and nano-scale crystalline indium-tin-oxide (c-ITO) patterns fabricated from amorphous ITO (a-ITO) thin films on a glass substrate using a (low NA 0.26) femtosecond laser pulse that is not tightly focused are demonstrated. Different types of c-ITO patterns are obtained by controlling the laser pulse energies and pulse repetition rate of a femtosecond laser beam at a wavelength of 1064 nm: periodic micro c-ITO dots with diameters of ~1.4 μm, two parallel c-ITO patterns with/without periodic-like glass nanostructures at a laser scanning path and nano-scale c-ITO line patterns with a line width ~900 nm, i.e. ~1/8 of the focused beam׳s diameter (7 μm at 1/e2).