  We propose a theoretical model for describing the operation of a transistor
with a MoS2 monolayer channel, which allows to obtain an analytical
approximation of the potential in the channel. This potential depends on the
drain and gate voltages. On this basis we make estimates for the minimum
channel lengths due to the fundamental restriction of quantum tunneling through
the barrier. It is shown that the relatively large effective mass of electrons
in the MoS2 monolayer allows to predict the creation of devices with channels
of a significantly shorter (2.5 - 3 nm) length than in traditional silicon
MOSFETs. These devices can be promising for the ultra-fast electronics of new
generation.
