  We calculated the electron mobility of 14 two dimensional semiconductors with
composition of MX$_2$, where M (= Mo, W, Sn, Hf, Zr and Pt) is the transition
metal, and X is S, Se and Te. We treated the scattering matrix by deformation
potential approximation. Long wave longitudinal acoustical and optical phonon
scatterings are included. Piezoelectric scattering in the compounds without
inversion symmetry is also taken into account. We found that out of the 14
compounds, WSe$_2$, PtS$_2$ and PtSe$_2$, are promising regarding to the
possible high electron mobility and finite band gap. The phonon limited
mobility in PtSe$_2$ reaches about 3000 cm$^2$V$^{-1}$s$^{-1}$ at room
temperature which is the highest among the compounds. The bandgap under the
local density approximation is 1.25 eV. Our results can be a guide for
experiments to search for better two-dimensional materials for future
semiconductor devices.
