Nano-structures for light management in optoelectronic devices

Two types of nano-structures are presented for light manipulation in semiconductor devices such as solar cells: (i) photonic-crystal-like structures for wavelength-selective manipulation of high reflectance or transmittance of light and (ii) diffraction gratings for angle-selective management of light scattering. Using optical simulations photonic-crystal-like structures with a high reflectance in the long-wavelength region are designed for a dielectric back reflector in solar cells. Structures formed by thin amorphous silicon and silicon dioxide layers are presented and the important role of refractive indexes and thicknesses of the individual layers is demonstrated. Haze and angular distribution function of scattered light are measured for aluminum based rectangular periodic gratings with different period and height of the rectangles