Optical Properties of Self-organized Silver Nano-island Thin Films

For wide-spread use and large-scale implementation of photovoltaic (PV) modules, a major improvement has to be made in both energy conversion efficiency and manufacturing cost. Improving light absorption, on both spatial and spectral domains, is a critical requirement in most PV cell designs. In thin-film solar cells, in particular, light usually is not completely absorbed in single pass transmission through the active layer, therefore proper ‘management’ of incident photons is particularly important. Plasmonic nanostructures can play a versatile role in mediating light-matter interactions, e.g., enhancing the scattering cross-sections (metal nanoparticles), concentrating the near field intensity (metal corners and nanoapertures) and coupling of light into waveguide modes (nanogratings), potentially beneficial for enhancing light absorption.\ud \ud In the study, optical properties of metal island thin films were characterized. Metal nano-islands were formed by performing thermal annealing of Ag films deposited on silica surface. The optical transmission, reflection, and extinction characteristics were analyzed for various incident angles as a function of film thickness and anneal temperature. The metal island formation is correlated to the evolution of transmission spectra, which involves surface plasmon resonance.\u