I– V methods to extract junction parameters with special emphasis on low series resistance

Abstract

We compare different I– V methods to extract junction parameters with a special emphasis on low series resistance determination. We have established the first method, the second method is based on the derivative (we use three formulae derived from d V/d I), the third method based on the integral (∫ Id V) and the final one which is the method of Lee et al. (Lee TC, Fung S, Beling CD, Au HL. J Appl Phys 1992;72:4739). The comparison is performed using a simulated case with random noise. The above methods give good results, especially the derivative although it is dependent on voltage step. The latter is not the case with our method. In addition this latter method is very simple to use. We also deal with a solar cell with two exponential conduction processes and a shunt resistance. The fitting of the curve gives good results and our method permits to determine the boundary between the two processes and to obtain good initial values for a numerical fit of the whole curve.