The effect of parasitic absorption losses on light trapping in thin silicon solar cells

The effect of parasitic absorption (PA) losses on light trapping in thin silicon cells was investigated. Parasitic absorption refers to an optical absorption process which does not generate an electron/hole pair; it competes with band-to-band absorption to decrease the photocurrent. A simple model for light trapping that includes PA is described for interpretation of experimental data. The sub-bandgap reflectance is shown to be a sensitive and quantitative indicator of PA losses. Minimization of the PA losses is shown to be as important as optimization of the light-trapping geometry for increased photogeneration in light-trapping thin silicon solar cells.