engleski

LIGHT TRAPPING ENHANCEMENT FOR SOLAR CELLS BY PLASMONIC Ag NANOPARTICLES

Plasmonics is an emerging field that benefits from nanoscale properties of metals. Generally metals support surface plasmons that are collective oscillation of excited free electrons and are characterized by a resonant frequency. By affecting the geometry of the nanoparticle, the surface plasmon resonance can be tuned. As the resonances of noble metals are mostly in the visible or infrared region of the electromagnetic spectrum their application in solar cells is expected. The surface plasmon resonance is affected by the shape and size of nanoparticles and by the dielectric properties of surrounding medium. Three different mechanisms can be exploited for photovoltaic application, which are: the scattering from the metal particles, the near field enhancement and direct generation of charge carriers in the semiconductor substrates. Most reported photocurrent enhancement results for inorganic devices are explained by the first mechanism of scattering. We deposited Ag thin films on clean Si substrate and on Si substrate covered with SiO2 films of different thickness. It is shown that the formation of Ag nanoparticles critically depends on the substrate temperature during deposition. All deposited films were subsequently annealed in high vacuum. The morphology of resulting samples was explored using atomic force microscopy, small-angle X-ray scattering and scanning electron microscopy as well as their size distribution and uniformity. Reflectance in UV-Vis range was used to study scattering from the nanoparticles before and after different treatments.

plasmonics; Ag; nanoparticles

nije evidentirano