MEASUREMENT OF CARRIER DIFFUSION LENGTH IN P-FeSiz THIN FILMS FOR SOLAR CELL APPLICATION

The minority carrier lifetime r in a p-FeSi2 film has been estimated by measuring the photocurrent decay and by fitting the decay curve according to the decay theory p-FeSi, films were prepared on Si substrates by molecular beam epitaxy technique. T was found to be more than IOpsec in all films, two orders greater than those in p-FeSi2 bulk samples. The diffusion length L was calculated from r and diffusion constant D that was obtained from Hall mobilities by using the Einstein relation. L was estimated to be longer than 20pm, much longer than the film thickness (0.3pm).