Surface recombination velocity and barrier width from surface photovoltage measurements

Data from surface photovoltage measurements on CdSe films are analyzed using two theoretical treatments. Only the more accurate theory is found to be satisfactory and yields values, not only of minority carrier-diffusion lengths, but also surface barrier widths and surface recombination velocities. The latter, for CdSe films in contact with alkaline sulfur redox systems, are in the range (4.5–12) ×105 cm s−1, leading to charge transfer velocities in the region of 4×105 cm s−1.