Product Code: ICAL07_N402

Fentosecond Laser-triggered Electrical Discharges at Nanoprobe Tips for Nanoprocessing
Authors:
Dave Farson, The Ohio State University; Columbus OH USA
Hae woon Choi, The Ohio State University; Columbus OH USA
Jian Chen, The Ohio State University; Columbus OH USA
Stanislav Rokhlin, The Ohio State University; Columbus OH USA
Presented at ICALEO 2007

The initial results on development of a surface modification and fabrication processes with an electrical discharge based nano-scale heat source are reported. Electrical discharges were stimulated by femtosecond laser pulses in nanoscale gaps between sharpened metal tips and gold film. Laser pulses with intensity 5.61011 W/cm2 reliably triggered discharges in sub-micron and microscale gaps. For gaps shorter than a threshold value, the discharge stimulation probability was near unity, independent of applied potential. At longer gaps the discharge probability abruptly decreased and then more gradually approached zero probability at a gap length that depended on voltage. At a lower laser intensity of 3.51011 W/cm2 , the discharge stimulation probability characteristics were similar to those at higher intensity, but only for the higher applied potentials (60V 80V) used. At lower applied potential, the discharge probability was also lower and depended on potential. With current limiting diode, the discharge current reached a peak value in about 2ns, and extinguished after an additional 2-3ns, irrespective of whether or not the discharge was laser stimulated. Scanning Electron Microscopy studies show gold surface regions was melted and re-solidified after electrical discharge. The shapes of modifications were similar but the size increased from about 500nm to 1μm as voltage varied from 40V to 80V.