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

The University of Florida 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. A critical assessment of the thermodynamic data and of the phase diagrams for the Cu-Se and In-Se binary systems were carried out. We investigated the use of two novel precursor structures that used stackedIn-Se and Cu-Se binary layers instead of conventional elemental layers, followed by rapid thermal processing (RTP) to produce CIS films. We investigated the evolution of electrical and microstructural properties of sputter-deposited ZnO:Al thin films. An assessment of the thermodynamics of the pseudobinary Cu2Se-Ga2Se3 system was done by using available experimental data, as well as an empiricalmethod for estimating interactions in semiconductor solid solutions. Optimization studies were conducted to characterize the RTP of binary bilayer precursors for CIS synthesis using a newly acquired AG Associates Heatpulse furnace. Progress was made on the calculation of the 500?C isothermal section of the phase diagram of the ternary Cu-In-Se system. Pursuit of developing alternative bufferlayers for Cd-free CIS-based solar cells using a chemical-bath deposition (CBD) process has resulted in specific recipes for deposition. A rigorous model has been derived to predict the metal mass fluxes produced by conical thermal effusion sources. A two-dimensional model of the heat transfer was developed to model the substrate temperature distribution in the UF PMEE Reactor that features arotating platen/substrates and effusion sources. We have grown and characterized polycrystalline CIS epitaxial films on single-crystal GaAs substrates under conditions that enhance the influence of surface effects on the resulting films and their properties. Progress was made on the study of CIS and CGS single-crystal growth, along with accompanying morphological and compositionalcharacterizations. We have developed physical models and performed numerical simulations using AMP-1D program to predict the performance of the CIS-based solar cells constructed with different buffer layers (such as CdS and Cd-free materials) and to compare the results with experimental data. A new computer-controlled automated measurement system for the characterization of the solar cellperformance parameters has been developed. The plasma-enhanced migration-enhanced epitaxial reactor (PMEE) is used for the deposition of a wide variety of thin CIS films. A new instrumentation and control interface for the plasma-enhanced migration-enhanced reactor has been designed and deployed to enable the implementation of advanced control strategies envisioned for the local sources, as wellas the supervisory control structure.