Determination of lifetime and diffusion length in silicon solar cells by self-biased (photovoltage) capacitance measurements

Many methods have been developed for the measurement of the diffusion length and lifetime of minority carriers in p-n junction solar cells. This paper presents a new technique for the measurement of these parameters, based on capacitance measurements in forward-bias condition at room and liquid air temperatures. In this experiment the solar cell was not biased by an external dc source, but was forward-biased by its own photovoltage generated by illumination. The results give 135 um diffusion length and 5.2 µsec lifetime of the minority carriers in a n+-p Si-solar cell.