  We report a transient absorption microscopy study of charge carrier dynamics
in bulk MoS2 crystals at room temperature. Charge carriers are injected by
interband absorption of a 555-nm pulse, and probed by measuring differential
reflection of a time-delayed and spatially scanned 660-nm pulse. We find an
intervalley transfer time of about 0.35 ps, an energy relaxation time of hot
carriers on the order of 50 ps, and a carrier lifetime of 180 ps. By monitoring
the spatiotemporal dynamics of carriers, we obtained a diffusion coefficient of
thermalized electrons of 4.2 cm2/s, corresponding to a mobility of 170 cm2/Vs.
We also observed a time-varying diffusion coefficient of hot carriers.
