Development of an intelligent design tool for non-stoichiometric compound devices: An example

In this paper, we discuss the idea of intelligent design of thin film CIGS solar cell, and we focus on the methodology of material design. We first introduce the calculation of the neutral defect concentrations of non-stoichiometric CuInSe₂, CuGaSe₂ and ZnO under specific atomic chemical potential conditions, and predict the formation of the order defect compound using the concept of minimization of total free energy, which includes the configurational entropy. This calculation is the main procedure in the material design and the key to the device design and process design. We then calculate the carrier concentrations using multi-level defect statistics and mobilities of these materials of different constitutions. The functions of the intelligent design tool are demonstrated.