Measurement of carrier diffusion length in /spl beta/-FeSi/sub 2/ thin films for solar cell application

The minority carrier lifetime /spl tau/ in a /spl beta/-FeSi/sub 2/ film has been estimated by measuring the photocurrent decay and by fitting the decay curve according to the decay theory. /spl beta/-FeSi/sub 2/ films were prepared on Si substrates by molecular beam epitaxy technique, /spl tau/ was found to be more than 10 /spl mu/sec in all films, two orders greater than those in /spl beta/-FeSi/sub 2/ bulk samples. The diffusion length L was calculated from /spl tau/ and diffusion constant D that was obtained from Hall mobilities by using the Einstein relation. L was estimated to be longer than 20 /spl mu/m, much longer than the film thickness (0.3 /spl mu/m).