Light-trapping silicon solar cells-experimental results and analysis

A method to identify and quantify light trapping in solar cells is presented. Light-trapping effectiveness depends on the internal reflectivity and texturing of device surfaces. The incorporation of light-trapping features can experimentally be seen in spectral response and reflectance measurements, as well as in the overall light-generated current. Due to the large number of variables that affect light-generated current, an analysis that evaluates only the optical properties of the structure is proposed. The effective optical path length of confined light is proposed as a figure of merit of the optical design. This effective optical path length is shown to be a function of wavelength. Analysis of the near-bandgap light is presented as a monochromatic case with appropriate specifications