  Layered transition metal dichalcogenides display a wide range of attractive
physical and chemical properties and are potentially important for various
device applications. Here we report the electronic transport and device
properties of monolayer molybdenum disulphide (MoS2) grown by chemical vapour
deposition (CVD). We show that these devices have the potential to suppress
short channel effects and have high critical breakdown electric field. However,
our study reveals that the electronic properties of these devices are at
present, severely limited by the presence of a significant amount of band tail
trapping states. Through capacitance and ac conductance measurements, we
systematically quantify the density-of-states and response time of these
states. Due to the large amount of trapped charges, the measured effective
mobility also leads to a large underestimation of the true band mobility and
the potential of the material. Continual engineering efforts on improving the
sample quality are needed for its potential applications.
