Ultra-lightweight amorphous silicon solar cells deposited on 7.5 /spl mu/m thick stainless steel substrates

To significantly reduce the solar cell weight and increase its specific power for space application, the authors deposited a-Si thin film solar cells on ultra-thin stainless steel (SS) substrates of 15 /spl mu/m, 12.5 /spl mu/m and 7.5 /spl mu/m thick and compared the results with those on standard 5 mil. (127 /spl mu/m) thick SS substrates that they use on a regular basis. To handle these ultra thin SS foils throughout the device fabrication process, they used a carrier method by attaching the ultra-thin SS foils on thicker 127 /spl mu/m SS substrates. They obtained ultra-lightweight solar cells that have similar performance as solar cells on regular 127 /spl mu/m substrates, with a V/sub oc/ of 0.887 V, a J/sub sc/ of 10.8 mA/cm/sup 2/, a FF of 68% and an efficiency of 6.5% for cells without back-reflector. These 6.5% efficient, rollable solar cells deposited on 7.5 /spl mu/m thick SS substrates exhibit a specific power of 1.08 kW/kg, significant for space power applications.