Lifetime and diffusion length of photogenerated minority carriers in single-crystalline n -type Β-Fe Si2 bulk

Abstract

We have evaluated the lifetime and diffusion length of photogenerated minority carriers (holes) in single-crystalline n -type Β-Fe Si2 bulk grown by chemical vapor transport. The diffusion length measured by optical-beam-induced current agreed well with that measured by electron-beam-induced current, that is, 51 and 38 μm, respectively, for samples annealed at 800 °C for 8 h. The decay curve of photoconductivity obtained by 1.31 and 1.55 μm light pulses was well fitted by assuming a carrier lifetime of approximately a few microseconds. The mobility of photogenerated minority carriers was estimated to be approximately 200-360 cm2 V s from the measured lifetime and diffusion length. © 2008 American Institute of Physics.