A novel plasmonic nanoantenna structure for solar energy harvesting

In this paper, five different nanoantenna structures, i.e. dipole, bowtie, rounded bowtie, rounded cross bowtie and cross bowtie nanoantennas are investigated for solar energy harvesting. Electrical field enhancement by each structure is investigated when different metals (silver, aluminum, gold, and copper) are used to achieve the best performance for solar energy harvesting. Field enhancement in the gap of the nanoantenna is defined as a figure of merit for comparing these structures. Simulations show that cross bowtie nanoantenna has the best performance for solar energy harvesting in the optical and infrared wavelengths. Moreover, genetic algorithm is used for optimizing nanoantenna geometry through Finite Element Method (FEM). Finally, the effect of thin layer oxidations on the cross bowtie nanoantenna is investigated, and the main fabrication issues such as effect of the manufacturing tolerances on the nanoantenna performance are discussed.