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Uncertainty in Photoconductance Lifetime Measurements that Use an Inductive-Coil Detector
K.R. McIntosh, R.A. Sinton
Calibration, Lifetime, Recombination, Silicon (Si)
Advanced Photovoltaics
Subtopic: Fundamental Studies
Event: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session: 1AO.6.2
77 - 82
ISBN: 3-936338-24-8
Paper DOI: 10.4229/23rdEUPVSEC2008-1AO.6.2
0,00 EUR
Document(s): paper


Photoconductance (PC) lifetime measurements are used widely within the photovoltaic industry but rarely are the results reported with any uncertainty. While nontrivial to determine, a knowledge of the experimental uncertainty is necessary to distinguish significant from insignificant differences between samples. This paper presents a preliminary study into the experimental uncertainty associated with PC instruments using inductive-coil detectors. Equations that express the uncertainty of (i) the excess carrier concentration and (ii) the effective lifetime are expressed in terms of the uncertainty of the input parameters, such as wafer width, calibration constants, and voltage resolution. The derivations illustrate why there is significantly less uncertainty in parameters extracted through transient rather than quasi-steady-state analyses. The paper also describes the difficulties associated with quantifying PC uncertainties that arise from the implicit relationship between carrier concentration and mobility, from the quantification of calibration errors, and in the case of transient analyses, from the quantification of the error in the voltage decay constant. One transient and one quasi-steady-state example is provided.