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HL: Fachverband Halbleiterphysik

HL 24: Joint Focussed Session: Thin Film Chalcogenide Photovoltaics III

HL 24.5: Talk

Monday, March 14, 2011, 17:00–17:15, GER 37

Pump-probe investigations on thin film ablation with ultra-short laser pulses — •Matthias Domke, Gerhard Heise, and Heinz Huber — Hochschule München

Laser lift-off processes have been observed during structuring CIGS thin film solar cells. To get a deeper insight in the underlying physical processes a pump-probe setup is used for spatial and temporal investigation of the interaction of ultra-short laser pulses with thin films. The setup consists of a 10 ps-laser pulse at a wavelength of 1064 nm that is split up into a pump and a probe beam. The pump beam is used to ablate thin films with single or multiple pulses. The probe beam illuminates the ablation area after an optically or electronically defined delay. A CCD Camera behind a microscope objective captures an image of the ultra-short exposed region. The probe beam is frequency doubled so that the pump light may be filtered out at the camera. Thus, the development of multiple pulse ablation is investigated in situ by taking pictures after each single pulse. Furthermore, a series of pictures can be taken on a picosecond time-scale by increasing the temporal delay of pump and probe beam. Consequently, the temporal evolution of direct and indirect (lift off) laser ablation of thin films can be studied.