CHARACTERIZATION AND MODELING OF CU(IN, GA)(S, SE)(2)-BASED PHOTOVOLTAIC DEVICES - A LABORATORY AND INDUSTRIAL PERSPECTIVE

This contribution is a summary of a workshop convened to discuss the c haracterization and modeling of thin-film CuInSe2(CIS)-based solar cel ls, 17-19 October 1993, in Estes Park, Colorado. The participants of t he workshop ave the authors of this paper. The subject matter was exam ined along four lines: device modeling, characterization, processing, and manufacturing issues. Fundamental numerical modeling has successfu lly guided device design efforts, including the design of variable ban d-gap,absorbers, Quantitative analysis, however, has been compromised by incomplete data on fundamental material properties. Phenomenologica l modeling and device characterization have successfully contributed t o the understanding of the device physics. Although classified as a he terojunction device, the forward-current recombination of the Zno/CdS/ CIS occurs almost exclusively in the space-charge with diode quality f actors ranging from 1.2 to 1.7 for good devices. The next generation o f device modeling must incorporate two- and three-dimensional effects. Recent fabrication work has focused on improving the CIS absorber and adding Ga and S to the matrix to increase its band-gap. A better unde rstanding of the ternary's fundamental properties is required to suppo rt the modeling efforts. Control of Ga and S introduction and the resu lting absorber band-gap profiles will facilitate the realization of op timized device designs. Inadequate understanding of fundamental device operation and process control at the laboratory level ave amplified i n the manufacturing environment. Modeling and characterization can ide ntify areas where corrective actions will result in improved performan ce and yield at the module level.