ИСТИНА

Silicon nanowires (SiNWs) were fabricated by metal-assisted chemical etching (MACE) where hydrofluoric acid (HF), which is typically used in this method, was changed onto ammonium fluoride (NH4F). The dependence of structural and optical properties of SiNWs from the pH of the etching solutions was observed. The formed SiNWs demonstrate a strong decrease of the total reflectance near 5-15 % in the spectral region λ < 1 µm in comparison to crystalline silicon (c-Si) substrate. The interband photoluminescence (PL) and Raman scattering intensities increase strongly for SiNWs in comparison with corresponding values of c-Si substrate. These effects can be interpreted as increasing of the excitation intensity of SiNWs due to the strong light scattering and the partial light localization in inhomogeneous optical medium. Along with the interband PL was also detected the PL of SiNWs in the spectral region of 500–1100 nm with maximum at 750 nm, which can be explained by the radiative recombination of excitons in small Si nanocrystals at nanowire sidewalls in terms of a quantum confinement model. So SiNWs, which is fabricated by environment-friendly chemistry, have a great potential for using in photovoltaics and photonics applications.