The paper describes the progress and current status of BP Solar's programme on Apollo thin film CdTe modules. It covers the latest improvements in process yield and module reliability, and discusses recent results from investigations of the semiconductor material properties. Results show that more than 90% of the solar cells are produced with efficiencies above 8% on 300 mm X 300 mm low cost substrates where the tin oxide has been deposited on the float glass line. In addition to the single plate modules, multiplate modules incorporating six plates in a 3 x 2 format under a monolithic front glass sheet have been fabricated with aperture area efficiencies up to 7.8%. The reliability of module performance has been assessed using environmental tests based on the CEC Specification 701 for thin film modules. The efficiency stability of the modules is measured outdoors in Spain by automatic monitoring of current-voltage characteristics and indoors with an accelerated test. Results of both tests show stable module efficiencies above 8.0%.
