Modeling conductivity as a function of temperature for CZTS and CZTSe thin film solar cell absorber layers

The goat of this project was to develop an accurate model for the temperature dependent conductivity of CU2ZnSnS4 (elTS) and CU2ZnSnSe4 {ClTSe} thin film solar cell absorber layers. Mathematical models of conductivity and resistivity were derived from both parallel and series combinations of temperature dependent charge carrier transport mechanisms. Specifically! this paper focuses on charge carrier transport associated with hopping, grain boundary, and freeze out mechanisms. These mechanisms were used to derive mathematical. expressions to model conductivity as a function of temperature. The mathematical models were subsequently incorporated into a computer program! and the models tested against experimental data using non-linear fitting methods. Using these procedures, some models were eliminated and others shown to be more probable in giving a good description of the measured conductivity for CZIS and ClISe absorber layers. The pbvsics incorporated into the successful models helps give insight into the dominanttransport processes in these thin films.