  We report a comprehensive study of ultrafast carrier dynamics in single
crystals of multiferroic BiFeO$_{3}$. Using femtosecond optical pump-probe
spectroscopy, we find that the photoexcited electrons relax to the conduction
band minimum through electron-phonon coupling with a $\sim$1 picosecond time
constant that does not significantly change across the antiferromagnetic
transition. Photoexcited electrons subsequently leave the conduction band and
primarily decay via radiative recombination, which is supported by
photoluminescence measurements. We find that despite the coexisting
ferroelectric and antiferromagnetic orders in BiFeO$_{3}$, the intrinsic nature
of this charge-transfer insulator results in carrier relaxation similar to that
observed in bulk semiconductors.
