  The temperature dependent band gap energy of Cu2ZnSnS4 thin film was studied
in the temperature range of 77 to 410 K. Various relevant parameters which
explain the temperature variation of the fundamental band gap have been
calculated using empirical and semi-empirical models. Amongst the models
evaluated, the Varshni and P\"assler models show the best agreement with
experimental data in the middle temperature range. However, the Bose-Einstein
model fits reasonably well over the entire temperature range evaluated. The
calculated fitting parameters are in good agreement with the estimated value of
the Debye temperature calculated using the Madelung-Einstein approximation and
the Hailing method.
