  The strong light emission and absorption exhibited by single atomic layer
transitional metal dichalcogenides in the visible to near-infrared wavelength
range makes them attractive for optoelectronic applications. In this work,
using two-pulse photovoltage correlation technique, we show that monolayer
molybdenum disulfide photodetector can have intrinsic response times as short
as 3 ps implying photodetection bandwidths as wide as 300 GHz. The fast
photodetector response is a result of the short electron-hole and exciton
lifetimes in this material. Recombination of photoexcited carriers in most
two-dimensional metal dichalcogenides is dominated by non-radiative processes,
most notable among which is Auger scattering. The fast response time, and the
ease of fabrication of these devices, make them interesting for low-cost
ultrafast optical communication links.
