February 27, 2008
FRONTIERS IN MATERIALS SCIENCE
VINSE COLLOQUIUM SERIES
Dr. Costas Grigoropoulos
Laser Thermal Laboratory
Department of Mechanical Engineering
University of California, Berkeley
"Laser-Assisted Micro/Nanoprocessing and Device Fabrication"
Abstract. Research on laser-assisted micro and nanoprocessing, nanomachining, nanolithography and nanodeposition is summarized. Fundamental aspects of ultrafast laser coupling with materials are probed by time-of-flight spectroscopy and time-resolved diagnostics. Femtosecond laser radiation enabled writing of 3-D microfluidic channels and hybrid opto-fluidic devices in glass. Pulsed lasers were coupled to near-field-scanning optical microscopes (NSOMs). Experiments have been conducted on the surface modification of metals, polymers and semiconductor materials in both ambient air and controlled gas environments. Ablation nanolithography and patterning has been demonstrated. NSOM-based ablation is applied to nanoscale chemical analysis. Interactions of pulsed laser radiation with nanostructures are investigated.
New methods are presented for the maskless fabrication of passive and active functional devices on flexible substrates utilizing nanoparticles in conjunction with laser processing and nanoimprinting. Low power, short-pulsed laser ablative material removal enabled finer electrical components to overcome the resolution limitation of inkjet deposition. Temporally modulated laser irradiation was utilized to locally evaporate the carrier solvent as well as sinter gold nano-particles, yielding low resistivity conductors. Selective multi-layered nanoparticle film processing was demonstrated. High-performance OFETs (organic field effect transistors) were demonstrated.