Determination of the minority carrier lifetime in solar cells: a novel biased OCVD technique

C.J. BRUNO; M.G. MARTÍNEZ BOGADO; J. PLA; J.C. DURÁN

PHYSICA STATUS SOLIDI A-APPLIED RESEARCH

WISLEY

Año: 1999 vol. 174 p. 231 - 238

0031-8965

A new simple method for the determination of the minority carrier lifetime (t), based on a biasedopen circuit voltage decay (OCVD) technique, is analyzed. In this case the excitation is given by apulsed light source (time dependent contribution) added to a continuous background illumination(continuous forward bias). Under appropriate conditions this configuration produces an exponentialvoltage decay with a time constant which depends on the bias. This constant tends to an effectivelifetime for the base region for large values of the bias voltage (typically, 400 to 500 mV). Aninexpensive equipment has been developed. Measurements have been made on several crystallinesilicon solar cells and on one high-efficiency float-zone silicon solar cell. Experimental results showgood agreement with the theoretical model presented and with numerical PC-1D simulations.