Skip to main content
. 2017 Oct 20;3(10):e1700232. doi: 10.1126/sciadv.1700232

Fig. 4. Fabrication of the bioinspired patterned thin PV absorbers.

Fig. 4

(A) Schematic view of the three main fabrication steps including the spin coating of a blend solution of poly(methyl methacrylate) (PMMA) and polystyrene (PS) in methyl ethyl ketone (MEK) on a thin a-Si:H layer deposited on a glass substrate, followed by a selective development of the PS, and finally the transfer of the pattern into a-Si:H by dry etching (RIE). (B) Image of a patterned 130-nm-thin a-Si:H layer on a glass substrate with completely etched disordered nanoholes (right) demonstrates the high omnidirectional absorption properties with respect to the unpatterned sample (left). All images are taken under diffusive white light with observation angles of 30° (top) and 80° (bottom). (C) SEM top-view image of the nanostructured a-Si:H thin film shows the distribution of nanoholes with both size and position disorders. The ring-shaped pattern in the 2D Fourier power spectrum corresponding to this SEM image (inset) confirms the correlated disordered nature of the nanoholes introduced in the thin absorber. (D) Statistical analysis of the nanohole diameters of this sample. The histogram depicting the distribution of nanohole diameters can be approximated by a Gaussian profile with a mean diameter of 238 ± 105 nm.