Nanostructuring of semiconductor materials and metallic thin films using femtosecond laser and scanning probe microscope

Ultra-short pulsed-laser radiation has been shown to be an effective tool for controlled material processing and surface nano/micro-modification because of minimal thermal and mechanical damage. Nanostructuring of a variety of materials is gaining widespread importance owing to ever-increasing applications of nanostructures in numerous fields. This study demonstrates that controllable surface nanostructuring can be achieved by effectively utilizing the local field enhancement in the near field of a SPM probe tip irradiated with femtosecond laser pulses. Results of nanostructuring of various metallic and semiconductor thin film samples utilizing an 800nm femtosecond laser system in conjunction with a commercial SPM in ambient air are presented. Additionally, results from a companion micro-ablation study on gold thin films and numerical Finite Difference Time Domain (FDTD) simulation results for the spatial distribution of the laser field intensity beneath the tip are presented in an effort to achieve better understanding of the laser-material interaction. Flexibility in the choice of the substrate material and the processing environment, high spatial resolution (∼10-12nm) and possibility of high processing rates by massive integration of the tips make this method an effective nanostructuring tool. Potential applications of this method include nanolithography, mask repair, nanodeposition, high-density data storage, as well as various nano-biotechnology related applications.