The use of the self-calibration method for accurate determination of silicon solar cell internal quantum efficiency

The application of the self-calibration method as a means of increasing the accuracy of spectral response, SR, and internal quantum efficiency, Q(λ), measurements is discussed. The principle of the method is the precise calculation of Q(λm) of a test cell for light at λm≈0.8 μm, where the response is weakly dependent on the emitter and base parameters. The ratio of the calculated and measured Q(λm) values gives the corresponding factor for shifting the experimental spectral response curve. The sequence of calculations is described, and an algorithm of the necessary operations for a computer is developed. Several examples of the use of the self-calibration method for correction of SR measurements of solar cells with low shunt resistance demonstrate its very high effectiveness. The corrected Q(λ) values follow the respective actual data with very high accuracy even when the measured SR is decreased by factor 2–3 due to low shunt resistance of the solar cell.