No abstract

The University of Florida subcontract entitled "Future CIS Manufacturing Technology Development" served as the basis for educating 12 graduate students in the area of photovoltaics engineering and research with a focus on thin-film CIS manufacturing technologies, and resulted in 23 research publications and presentations. Further details are given in Part 1 of this report.A critical assessment of the thermodynamic data and of the phase diagram for the Cu-Se binary system was carried out. It was determined that the compounds of this I-VI system exhibit a wide variety of properties. For example, Cu 2-x Se behaves as mixed conductor, showing both ionic and electronic conduction, and it is often present in CuInSe 2 -based solar cells as an undesirable secondary phase. In contrast, the CuSe 2 phase is a low-temperature superconductor. Knowledge of the thermochemistry and phase diagram of the Cu-Se system is essential for understanding the ternary Cu-In-Se system and its subsequent use in developing new CIS processes. In producing a critical assessment of the Cu-Se system we used an association model to describe the liquid phase, and a three-sublattice compound energy formalism to describe the Cu 2-x Se phase. The remaining intermediate solid phases (Cu 3 Se 2 , CuSe, CuSe 2 ) were modeled as line compounds. As a result, a self-consistent set of phase diagram and thermodynamic data was obtained. Further details are given in Part 2 of this report.