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Photoconductance-based excess carrier lifetime measurements on unpassivated silicon samples

 
: Roth, T.; Rosenits, P.; Warta, W.; Glunz, S.W.

:
Fulltext urn:nbn:de:0011-n-1436012 (125 KByte PDF)
MD5 Fingerprint: 8fec21c53875dd2b8fe80fd2f1acf282
Created on: 31.8.2012


Sinke, W. ; WIP - Renewable Energies, München; European Commission; UNESCO; World Council for Renewable Energy; International Photovoltaic Equipment Association:
24th European Photovoltaic Solar Energy Conference 2009. CD-ROM : The compiled State-of-the-Art of PV Solar Technology and Deployment. Proceedings of the International Conference held in Hamburg, 21-25 September 2009
München, 2009
ISBN: 3-936338-25-6
pp.2004-2007
European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC) <24, 2009, Hamburg>
English
Conference Paper, Electronic Publication
Fraunhofer ISE ()

Abstract
Measurement techniques which rely on the exact knowledge of the actual generation rate within a silicon sample (such as quasi-steady-state photoconductance measurements) are significantly affected by spectral variations of the illumination source. This is especially the case when using supplementary long-pass filters, in order to ensure a more symmetrical excess carrier profile within lowlifetime silicon samples. In this contribution the effect of different illumination spectra on photoconductance-based lifetime measurements will be investigated in detail. The calculations are based on reliable measurements of the optical properties of the samples and the reference cell, as well as the used photo flash spectra. Two different simple approaches to calculate the excess carrier generation rate are presented and compared. Evaluations are exemplarily performed on a set of unpassivated thicknessvaried silicon samples, revealing generation rate deviations as high as 21 % for different sample thicknesses and illumination spectra. Additionally, the effect of the different excitation spectra on the measured effective lifetime will be shown.

: http://publica.fraunhofer.de/documents/N-143601.html