Plasmon-enhanced deep-subwavelength lateral nanowire solar cells

High performance deep-subwavelength lateral GaAs nanowire solar cells decorated with Au nanoblocks are proposed and studied through coupled three-dimensional optoelectronic simulations. The results show that Au nanoblocks significantly improve the absorption for TE polarized light mainly due to the excitation of localized surface plasmon. Surface local and near-field enhancement are two unique properties of surface plasmon, which concentrate light and transfer energy to nanowires. In addition, the absorption cutoff wavelength is remarkably extended due to the effect of localized surface plasmon resonance which enhances the confinement of long-wavelength modes for deep-subwavelength nanowires. For the nanowire with diameter less than 150 nm, the photoelectric conversion efficiency is improved by 37~43% after introducing Au nanoblocks, which can reach 12% for 90 nm-diameter nanowire. This study presents a viable approach for achieving high-performance deep-subwavelength nanowire solar cells.