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

We compare different I-V methods to extract junction parameters with a spec ial emphasis on low series resistance determination. We have established th e first method, the second method is based on the derivative (we use three formulae derived from dV/dI), the third method based on the integral (integ ral IdV) 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 resu lts, especially the derivative although it is dependent on voltage step. Th e 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 an d a shunt resistance. The fitting of the curve gives good results and our m ethod permits to determine the boundary between the two processes and to ob tain good initial values for a numerical fit of the whole curve. (C) 1999 E lsevier Science Ltd. All rights reserved.