  We present a computational study on the impact of tensile/compressive
uniaxial ($\varepsilon_{xx}$) and biaxial ($\varepsilon_{xx}=\varepsilon_{yy}$)
strain on monolayer MoS$_{2}$ NMOS and PMOS FETs. The material properties like
band structure, carrier effective mass and the multi-band Hamiltonian of the
channel, are evaluated using the Density Functional Theory (DFT). Using these
parameters, self-consistent Poisson-Schr\"{o}dinger solution under the
Non-Equilibrium Green's Function (NEGF) formalism is carried out to simulate
the MOS device characteristics. 1.75$%$ uniaxial tensile strain is found to
provide a minor (6$%$) ON current improvement for the NMOSFET, whereas same
amount of biaxial tensile strain is found to considerably improve the PMOSFET
ON currents by 2-3 times. Compressive strain however degrades both NMOS and
PMOS device performance. It is also observed that the improvement in PMOSFET
can be attained only when the channel material becomes indirect-gap in nature.
We further study the performance degradation in the quasi-ballistic long
channel regime using a projected current method.
