Modeling of multilayer SiGe based thin film solar cells

Simulations using PC1D have been performed to demonstrate the viability of crystalline SiGe alloys implementation in thin film solar cells. An optimized structure would consist of a p-type doped SiGe layer, capped with a Si p-n junction at the top, and a Si BSF at the bottom. Further refinements in such cell structure include a gradual compositional profile of the SiGe alloy layer. Compared to a conventional Si thin film cell, up to 5% relative efficiency gain is demonstrated, for a 20 /spl mu/m thick SiGe layer with less than 10% Ge content, p-type doped to more than 1 10/sup 17/ cm/sup -3/, and a realistic minority carriers diffusion length of the order of the layer thickness.