Fig. 1 a) Overall structure of the solar cell. Photonic light trapping structure, here depicted for the random case, is present only into the active Si layer. In the figure r is the radius of the holes, a, t, b and h are the thicknesses of the ARC, the active layer (a-Si or c-Si), the Ag backreflector and the depth of the holes. Realization (8 × 8 μm²) of b) periodic (hexagonal lattice) c) correlated disordered and d) random hole patterns. The calculation for v the periodic case has been performed on a computational cell of $D\times \sqrt{3}D$D, where D is the distance between holes (D = 644 nm), due to the periodicity of the system. Thus, the image in b) does not represent the actual computational cell but is a schematic representation of the periodic structure for comparison with c) and d).

Fig. 2 a) and c) Calculated absorption spectra and b) and d) respective absorption enhancements for a-Si solar cells with periodic, correlated-disordered and random photonic structures for configuration A1 and A2.

Fig. 3 a) and c) Calculated absorption spectra and b) and d) respective absorption enhancements for c-Si solar cells with periodic, correlated-disordered and random photonic structures for configuration C1 and C2.