Future CIS Manufacturing Technology Development: Final Report, 8 July 1998--17 October 2001

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.

First-principle investigation of structural, electronic, and phase stabilities in chalcopyrite semiconductors: insights from Meta-GGA functionals

“…Comparisons of absolute values of formation enthalpies in eV per atom of the chalcopyrite and the binaries calculated by PBE and meta-GGA with reference data for AgInSe 2 [73], In−Se binaries [93] and Ag−Se binary [94].…”

What is Happening with Regards to Thin-Film Photovoltaics?

“…Past work was carried out along these lines (Attar et al 1994) . Similarly, advantages of CuSe or InSe precursors have not as yet been demonstrated to lead to high solar cell efficiencies (Anderson et al 2003). In addition to films made by the former process having problematic mechanical film properties (flaking), rapid post-deposition selenization approaches have also not yet lead to great solar cell efficiency.…”