TOWARD A THEORETICAL LIMIT OF SOLAR-CELL EFFICIENCY WITH LIGHT TRAPPING AND SUBSTRUCTURE

The performances of Si - n+ - p solar cells are calculated using the c ell width as a parameter and taking into account light trapping effect and infrared light excitation due to the inclusion of a defect layer near the n - p junction. A model is developed to describe light confin ement and optimized cell structures are considered. The low absorption of long wavelength photons in thin solar cells is shown to be compens ated by the light confinement. Higher values of the maximum output pow er are obtained and the effect is particularly significant for thin ba se cells (H < 60 mum) with a 3.5 mW cm-2 maximal increase of the maxim um output power.