Cost-effective laser patterning of indium tin oxide (ITO) thin film coated on flexible polyethylene terephthalate (PET) film substrate for touch panel was studied. The target scribing width was set to the order of 10 μm in order to examine issues involved with higher feature resolution. Picosecond-pulsed laser and Q-switched nanosecond-pulsed laser at the wavelength of 532nm were applied for the comparison of laser patterning in picosecond and nanosecond regimes. While relatively superior scribing quality was achieved by picosecond laser, 532 nm wavelength showed a limitation due to weaker absorption in ITO film. In order to seek for cost-effective solution for high resolution ITO scribing, nanosecond laser pulses were applied and performance of 532nm and 1064nm wavelengths were compared. 1064nm wavelength shows relatively better scribing quality due to the higher absorption ratio in ITO film, yet at noticeable substrate damage. Through single pulse based scribing experiments, we inspected that reduced pulse overlapping is preferred in order to minimize the substrate damage during line patterning.
While utilization of renewable solar energy by converting to electricity via photovoltaic (PV) solar cells is one promising route to meet urgent energy needs without involving fossil fuel consumption or carbon dioxide emission, the challenge lies on reducing the cost per watt to compete with traditional fossil fuel technology. To this end, developing low cost PV manufacturing technologies at improved manufacturing and device efficiencies is primary challenge to ensure that solar energy is a viable and economic source for power needs. In this paper, recent efforts on short pulsed laser scribing processes of CIGS (Copper Indium Gallium Diselenide) thin film solar cells will be demonstrated. High repetition rate (~ 100 kHz) picosecond laser based results are compared with those by nanosecond laser. Advantages and limitations of picosecond laser scribing process will be discussed, and a tentative solution based on cost-effective nanosecond lasers will be proposed. A further improved scribing quality and accuracy will be also attempted by gas injection scheme.
Extensive research in micro/nanoscale surface engineering has developed a variety of energy applications including improvement of light trapping performance in solar cells, and increased surfaced area on electrodes in batteries or fuel cells applications with extended life time. In this study, we are aiming to the evaluation of a cost effective surface texturing method based on rapid scanning of nanosecond laser pulses. In contrast to conventional laser-assisted methods, we have achieved highly uniform and controllable texturing means over arbitrary scanning area of semiconductor and metallic surfaces.