TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The domes are arranged in an arrangement that is aperiodic in one or two dimension(s), and have a first periodicity that is greater than the first band-gap wavelength. The article further comprises: a second layer that is substantially conformal with the first composite layer, where the second layer comprises a first material having a refractive index that is lower than the refractive index of the first composite layer, and where the first composite layer interposes the substrate and the second layer; or a second layer that is substantially reflective for light having a wavelength of 400-1600 nm, where the second layer interposes the substrate and the first composite layer, where the second layer comprises a surface modulation which induces light-absorption enhancement in the first composite layer, and where the first composite layer and the second layer collectively define a photonic waveguide. The second layer and first composite layer collectively have a lower reflectivity than the first composite layer for light having a wavelength of 400-1600 (preferably 400-800) nm. The second layer has an effective graded refractive index profile. The article further comprises: a third layer that is substantially conformal with the first composite layer, where the third layer comprises a first material having a refractive index that is lower than the refractive index of the first composite layer; a second composite layer comprising many domes, where the second composite layer is an optically active layer having the first or a second band-gap wavelength, where the second composite layer is disposed on the first composite layer, and where each of the first composite layer and second composite layer comprises a solar cell layer structure; or a surface that is characterized by a water-contact angle that is greater than or equal to 140 degrees . The first composite layer interposes the second layer and the third layer, where first composite layer, second layer, and third layer collectively define a photonic waveguide. The first composite layer: comprises a solar cell layer structure comprising p-doped hydrogenated amorphous silicon disposed on substantially intrinsic hydrogenated amorphous silicon disposed on n-doped hydrogenated amorphous silicon; and has a thickness of 50-5000 (preferably 200-500) nm. Preferred Method: The substrate is provided such that the substrate has an array of projections, where each dome is formed on a different projection, and where the array of projections has a first periodicity that is less than or equal to the first band-gap wavelength. The substrate is provided by operations comprising: forming a mask on the substrate comprising a first material having a first etch rate in an etchant, where the substrate comprises a second material having a second etch rate in the etchant, and where the second etch rate is greater than the first etch rate; and etching the mask and substrate in the etchant. The mask is formed by disposing a monolayer of particles of the first material on a surface of the substrate. The first composite layer is formed by conformally depositing at least one semiconductor layer on the substrate such that each dome is formed on a different projection. The method further comprises forming a second layer which interposes the first composite layer and the substrate, where the second layer is substantially reflective for light having a wavelength of 400-800 nm. The second layer is formed such that it comprises: a surface modulation that induces enhanced light absorption in the first composite layer; or a photonic waveguide for receiving and scattering light that has transited the first composite layer. The method further comprises: forming a second layer that is substantially conformal with the first composite layer; forming a second layer that is substantially conformal with the first composite layer, where the second layer is electrically conductive, and forming a second composite layer that is substantially conformal with the second layer, where second layer interposes the first composite layer and the second composite layer, and where the second composite layer is an optically active layer having the first band-gap wavelength; forming a second layer that is substantially conformal with the first composite layer, and forming a second composite layer that is substantially conformal with the second layer, where the second composite layer is an optically active layer having the second band-gap wavelength; or forming a second layer, where the first composite layer interposes the second layer and the substrate, and where the second layer comprises a surface having the water-contact angle mentioned above. The first composite layer is formed by: conformally depositing many semiconductor layers which collectively define a solar cell layer structure; operations comprising conformally depositing the first semiconductor layer, conformally depositing the second layer of semiconductor on the first semiconductor layer, and conformally depositing the third layer of semiconductor on the second semiconductor layer; or conformally depositing many semiconductor layers which collectively define a light-emitting diode layer structure, a photodetector layer structure or an optical modulator layer structure.