Berlin 2005 – scientific programme

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HL: Halbleiterphysik

HL 58: Poster IIb

HL 58.44: Poster

Tuesday, March 8, 2005, 16:30–19:00, Poster TU F

Local characterisation of multicrystalline silicon solar cells with the front metal grid on grain boundaries — •Viktor Schlosser¹, Rita Ebner², and Johann Summhammer² — ¹Institut für Materialphysik, Universität Wien — ²Atominstitut der Österreichischen Universitäten, Wien

Light beam induced current mapping (LBIC) is used to investigate large area solar cells. Multicrystalline silicon solar cells were equipped with a front metal grid which was applied onto the grain boundaries. The LBIC experimental set up works with two fibre coupled luminescence diodes at centre wavelengths of 650 nm and 870 nm respectively. The two LEDs were driven by the same current and individually intensity modulated. By the use of two Lock In amplifiers the total light generated current from the device was split into its two components. A feed back loop for the LED current was used to maintain a constant LBIC signal of the red LED. The current caused by the infrared LED was recorded as a function of the light spot position on the solar cell. By this method the contribution of many of the surface’s electrical and optical inhomogenities to the LBIC were eliminated. The scanned signal merely is altered by the local bulk properties of the carriers. The results made on cells under different operating conditions will be presented and discussed.