Prediction of photovoltaic Cu(In,Ga)Se2 p-n device performance by forward bias electrochemical analysis of only the p-type Cu(In,Ga)Se2 films
D. Colombara, T. Bertram, V. Depredurand, T. Fouquet, J. Bour, C. Broussillou, P. P. Grand, and P. J. Dale
ECS Transactions, vol. 66, no. 6, pp. 19-25, 2015
This work is an attempt to rate the quality of Mo/Cu(In,Ga)Se2 films intended for fabrication of photovoltaic devices. The procedure is based on the simple current-voltage electrochemical analysis of the bilayer in a Eu2+/3+-containing electrolyte solution. Two series of bilayer samples were tested electrochemically, while sister samples were completed into Mo/Cu(In,Ga)Se2/CdS/i-ZnO/Al:ZnO/Ni-Al solid state devices and their current-voltage characteristics measured in the dark. A correlation was found between the reverse saturation current density of the solid state devices and an analogous parameter extracted from the electrochemical response in forward bias. While Eu2+ was found to be metastable in water posing restrictions to the application, reproducible measurements were achieved with a methanol-based solution. The intrinsic simplicity of the proposed methodology makes it particularly suitable for the implementation of a low-cost diagnostic tool.