  The performance limits of monolayer transition metal dichalcogenide
transistors are examined with a ballistic MOSFET model. Using ab-initio theory,
we calculate the band structures of two-dimensional (2D) transition metal
dichalco-genide (MX2). We find the lattice structures of monolayer MX2 remain
the same as the bulk MX2. Within the ballistic regime, the performances of
monolayer MX2 transistors are better compared to the silicon transistors if
thin high-{\kappa} gate insulator is used. This makes monolayer MX2 promising
2D materials for future nanoelectronic device applications.
