Novel porous silicon backside light reflector for thin silicon solar cells

High efficiencies of thin crystalline Si solar cells grown on highly doped substrates have been reported We propose par aus Si layers located near the interface of the active layer and the substrate to introduce an optical co nfinement into these cells, We report on the experimental proof of the prin ciple for this novel type of hack-surface reflector. Spectral reflectance m easurements agree well with computer simulations, On the basis of this agre ement, we calculate the enhancement of short-circuit current densities due to porous reflectors for textured and non-textured cells, These simulations are of particular relevance for multicrystalline Si cells on foreign subst rates and for space cells. (C) 1998 John Wiley & Sons, Ltd.