Generalized models of the spectral response of the voltage for the extraction of recombination parameters in silicon devices

Analytical models of the spectral response of the voltage of silicon devices have been generalized using the concept of the internal quantum efficiency of the semiconductor. This allows the extension of models used in the analysis of the internal quantum efficiency to the spectral response of the voltage. Existing models for the spectral response of the voltage that are largely employed in the surface photovoltage technique are shown to be special cases that approximate the internal quantum efficiency. A more sophisticated model of the internal quantum efficiency, the model of Isenberg, and a model that allows the analysis of the internal quantum efficiency of rear-illuminated devices have been adapted to the spectral response of the voltage. This paves the way to analyze solar cells, Schottky devices, or chemically treated silicon wafers independently of the light intensity and using front or rear illumination. The models have been validated by comparing the analysis of the spectral response of the short-circuit current and the open-circuit voltage with computer simulations for a wide range of solar cells. The model of Isenberg has been found to give in general the best prediction of the recombination parameters for both the spectral photocurrent and photovoltage. The analysis of the spectral response of the voltage can often unveil the surface recombination rate where the spectral photovoltage fails to produce any output. The measurement of rear-junction cells showed that the surface recombination rate can be predicted equally well with either method.