Use of VOC/JSC measurements for determination of barrier height under illumination and for fill-factor calculations in Schottky-barrier solar cells

An experimental study has been made of metal-silicon solar cells, with thin Ag, Au, Cu, Fe and In electrodes. No intentional interfacial layers were introduced and the silicon surfaces were chemically prepared in such a way as to minimise the residual oxide layer. The characteristics of the devices were taken at various illumination levels and the effect of barrier height, series resistance and n-value on the open-circuit voltage and the fill factor were studied. Comparison between theoretical predictions and the experimental results show that Voc/Jsc measurements that provide the n-values appropriate for the expression for the open-circuit voltage also provide a reliable method for experimental barrier-height determination under illumination and that the above `true¿ n-value should also be used in fill-factor calculations.