A study of energy band gap versus temperature for Cu2ZnSnS4 thin films

The temperature dependent band gap energy of Cu2ZnSnS4 thin film was studied in the temperature range of 77–410 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 Pässler 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.