Improved solar spectrum optical absorption in multilayered nanostructures
consisting of metal, semiconductor and dielectric layers increase their
potential for efficient photon to electron conversion. In this work, we analyze
the influence of different nanostructure shapes and dimensions on the optical
absorption in the vacuum wavelength range of 400 nm to 1500 nm based on Finite
Domain Time Difference (FDTD) method. A periodic metallic photonic crystal
composed of nanorods of gold, titanium oxide, and alumina is proposed by
optimizing thickness of Au and TiO2, aspect ratio, sidewall angle,
and geometry of the elemental shape. A high aspect ratio structure consisting of
elliptical nose cone elements with optimized dimensions is seen to absorb more
than 90% of the solar spectrum in the range considered.