  Band structure of InSb thin films with $<100>$ surface orientation is
calculated using empirical pseudopotential method (EPM) to evaluate the
performance of nanoscale devices using InSb substrate. Contrary to the
predictions by simple effective mass approximation methods (EMA), our
calculation reveals that $\Gamma$ valley is still the lowest lying conduction
valley. Based on EPM calculations, we obtained the important electronic
structure and transport parameters, such as effective mass and valley energy
minimum, of InSb thin film as a function of film thickness. Our calculations
reveal that the 'effective mass' of $\Gamma$ valley electrons increases with
the scaling down of the film thickness. We also provide an assessment of
nanoscale InSb thin film devices using Non-Equilibrium Green's Function under
the effective mass framework in the ballistic regime.
