ULTRATHIN CRYSTALLINE SILICON SOLAR-CELLS ON GLASS SUBSTRATES

We fabricate thin crystalline silicon solar cells with a minority carr ier diffusion length of 0.6 +/- 0.2 mu m by direct high-temperature ch emical vapor deposition on glass substrates, This small diffusion leng th does not allow high cell efficiencies with conventional cell design s. We propose a new cell design that utilizes submicron thin silicon l ayers to compensate for low minority carrier diffusion lengths. Accord ing to theoretical modeling, our design exhibits excellent light trapp ing properties and allows for 10% efficiency at an optimum cell thickn ess of 0.4 mu m only. This submicron range of cell thicknesses was for merly thought to require direct band gap semiconductors. (C) 1997 Amer ican Institute of Physics.