A new method for the determination of the minority carrier lifetime based on a biased OCVD technique [solar cells]

A new simple method for the determination of the solar cell minority carrier lifetime (τ), based on a biased OCVD technique, is analyzed. In this case, the excitation is given by a pulsed light source (time dependent contribution) plus a continuous illumination (continuous forward bias). Under appropriate conditions, this configuration produces an exponential decay with a time constant which depends on the bias. This constant decreases monotonously as a function of bias and allows one to determine an effective τ for the base region. Inexpensive test equipment has been developed which basically consists of two sets of high-efficiency GaAs LEDs, which provide both light contributions. Measurements have been performed on crystalline silicon solar cells elaborated in the Argentine Atomic Energy Commission. Experimental results show good agreement with the theoretical model and with numerical PC-1D simulations