We have produced single-wall carbon nanotubes (SWNTs) by Nd:Yag laser vaporization of porous cobalt-nickel/graphite targets for the first time without applying external heat to the target. Both continuous wave (c.w.) and pulsed laser-techniques were explored. In the pulsed experiments, the energy density per pulse was varied between 0.12 and 0.62 J/cm2 and pulse rates ranged from 24 kHz down to 3 kHz corresponding to average powers of 25.5 to 16 W. Continuous wave experiments were conducted at average powers which corresponded to those measured for each of the pulsed runs. An additional run at 30 W was also performed. A rigorous method developed for the analysis of transmission electron microscopy (TEM) images was used to estimate SWNT content in the laser-generated carbon samples. The pulsed and continuous wave processes both produced a linear increase in SWNT content with increasing average power. These results are not intuitive for the pulsed laser-production since a higher average power corresponds to a lower peak pulse power. In fact, a pulsed run with the maximum pulse energy of 0.62 J/cm2 (3 kHz, 16 W), produced no detectable SWNTs. A maximum SWNT content of 78% was observed for c.w. experiments at a power of 30 W. Additional laser experiments performed on dense cobalt-nickel / graphite targets at room temperature enabled a better understanding of the carbon removal mechanisms for the pulsed versus c.w. processes. Cumulatively, these investigations indicate that high energy laser pulses produce particles from highly porous targets by ablation which are too large to readily be incorporated into growing nanotubes. Successful high-yield production of SWNTs relies upon remaining in a vaporization regime during synthesis.

A theoretical model for removal of tiny particles from solid surface covered with a thin liquid film by laser cleaning is established by taking adhesion force and cleaning force into account. When pulsed laser irradiates on the solid surface coated with a thin liquid film, a sheet of liquid near the liquid/substrate interface can be superheated through thermal diffusion. The rapid growth of vapor bubbles inside the superheated liquid can generate transient stress wave with high pressure, large enough to expel micron and sub-micron particles from the contaminated surface. By calculating the adhesion force and cleaning force, the cleaning threshold of laser fluence can be predicted from this theoretical model. The difference between cleaning force and adhesion force increases quickly along with the laser fluence and leads to higher cleaning efficiency.

A relatively new approach in removing the sidewall and bottom polymers resulting from reactive ion etching of via holes, using a non-contact dry excimer laser cleaning technique has been investigated. Pulsed excimer laser ablation at 248 nm has been found to be capable of removing the via-etch-induced polymers at fluences limited by the damage threshold of the underlying Al-Cu metal film with TiN anti-reflective coating of 250-280 mJ cm-2. A fluence window of 150-200 mJ cm-2 for efficient laser cleaning is also determined from the ablation rate data using the relation in the limit of Beer's law absorption. Experimental results have also shown that the ablation rate when irradiating at an angle is not only comparable to that at vertical incidence, but even register higher values for most of the ablation rate data obtained. An optimum incident angle for laser cleaning of 45° can be determined from the results.

A novel variation of conventional pulsed laser deposition, called matrix assisted pulsed laser evaporation, or MAPLE, has been utilized for growing organic thin films. The MAPLE technique is carried out in a vacuum chamber and involves directing a pulsed laser beam) onto a frozen target consisting of an organic compound dissolved in a solvent matrix. The laser beam evaporates the surface layers of the target with both solvent and organic molecules being released into the chamber. The volatile solvent is pumped away, whereas the organic molecules coat the surface of a substrate. Very thin and uniform films (50 to 100 nm) of various organic materials, such as carbohydrates, have been deposited on Si(111) and NaCl substrates. The films prepared using this method have been examined by optical microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and electrospray mass spectrometry. Careful control of the processing conditions allowed carbohydrates such as sucrose and glucose, in addition to high molecular weight polymers such as dextran, to be transferred to the substrate as uniform films, without significant chemical decomposition. The use of MAPLE films for chemical and biological sensor applications is being investigated and the potential of this technique for producing high quality thin films of other organic compounds will be discussed.