Shifting the Aluminum nanoparticle plasmon resonance to the visible with SiN and a-Si thin films

Metal nanoparticles have strong optical resonances, which can be used to enhance optical absorption, particularly in thin film solar cells. Most research on these plasmon resonances in the context of solar cells has been performed on gold and silver nanoparticles. As these materials are expensive, alternatives are needed. Aluminum nanoparticles have a plasmon resonance in the UV, but by embedding these particles in silicon nitride or amorphous silicon, the plasmon resonance can be shifted to the visible part of the spectrum. Using a gas aggregation cluster source for the particles and magnetron sputtering for the thin films, aluminum nanoparticles were embedded in silicon nitride and amorphous silicon thin films, which shifted the optical resonance of the metal nanoparticles. The optical absorption of particles embedded in amorphous silicon was not at the expected wavelength, but the results of particles embedded in silicon nitride were in good agreement with FDTD simulations. This work is a next step for cheap plasmonics in solar cells