INVESTIGATION OF THIN FILM CADMIUM SULFIDE SOLAR CELLS.
Quarterly technical progress rept. no. 2, 25 Feb-25 May 64
HARSHAW CHEMICAL CO CLEVELAND OHIO
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Considerable emphasis has been placed on the development of the chemiplated or immersion technique for the barrier formation. Gains of about 40 in conversion efficiency have been realized over the standard efficiency of 2.5. Lighter weight solar cells have been fabricated on titanium substrates with high power to weight ratios. Solar cells using H-film as the substrate material have been made with efficiencies of over 4 and power to weight ratios greater than 40. The vacuum deposition of CdS on single crystal CdS has been performed to study effects of substrate perfection on the quality of the film. Solid state reactions of CuC1 and CdS were investigated in order to prepare more effective barriers. Indium plated Mo substrates were utilized to provide ohmic contacts at the CdS substrate interface. Spectral response of electroplated and chemiplated cells as a function of time shows that the latter appear to be more stable in ordinary ambients. The use of SiO thin films on the top surface of the cells has led to a more stable cell in the presence of water vapor. Optical studies on the chemiplated barrier layer have confirmed a Cu2-xS compound of a thickness of about 1800A and exhibiting free carrier absorption. Theoretical work has been limited to a model based on surface states. Author