Size and period optimization of front patterned interacting metal nanoparticles for maximizing absorption of solar radiation in amorphous silicon thin films

Plasmonic assisted enhancement of optical absorption within a thin layer of amorphous silicon (a-Si:H) by incorporating a periodic array of spherical metal nanoparticles on the front side of the a-Si:H layer has been demonstrated by solving Maxwell's curl equations using a finite difference time domain (FDTD) method. For different particle sizes between 40 and 80 nm, the interparticle spacing has been optimized to yield maximum absorption of AM1.5G solar radiation. By increasing the interparticle coupling, a red-shift up to 280 nm is observed in the peak of broadband absorption behavior within a-Si:H layer. Meanwhile, a comparison between spherical Ag, Al and Au nanoparticles of fixed size is made with respect to the optical absorption enhancement within a-Si:H for the wavelength range from 400 to 800 nm from which we can choose the wavelength range over which a particular type of metal nanoparticle will be useful.