Figure 2.

Optical Response with Optimized TiO₂ Half-Spheroids Array

(A–C) Absorption spectra attained with the optimized LT structure sketched in Figure 1A composed of half-spheroids (red curves, row 3 of Table 1), and with the reference cases of an unpatterned cell (purple, row 1) and a cell with an optimized AZO anti-reflection coating (black, row 2), for three absorber layers: (A) 100-nm a-Si, (B) 300-nm a-Si, and (C) 1.5-μm c-Si. Each graph shows the absorption occurring in Si (solid lines) and the parasitic absorption in the other materials (colored regions above the lines).

(D–I) The bottom profiles show the log-scale distribution of the total generation rate, G (see Section S1.1 in Supplemental Information), along the xz cross-sectional plane of the structures at y=0. (D), (F), and (H) correspond to the reference cells with ARC, and (E), (G), and (I) correspond to those with the half-spheroids, respectively, for the 100-nm a-Si, 300-nm a-Si, and 1.5-μm c-Si absorbers.