Doubling absorption in nanowire solar cells with dielectric shell optical antennas

Sun Kyung Kim, Xing Zhang, David J. Hill, Kyung Deok Song, Jin Sung Park, Hong Gyu Park, James F. Cahoon

Research output: Contribution to journalArticlepeer-review

102 Citations (Scopus)


Semiconductor nanowires (NWs) often exhibit efficient, broadband light absorption despite their relatively small size. This characteristic originates from the subwavelength dimensions and high refractive indices of the NWs, which cause a light-trapping optical antenna effect. As a result, NWs could enable high-efficiency but low-cost solar cells using small volumes of expensive semiconductor material. Nevertheless, the extent to which the antenna effect can be leveraged in devices will largely determine the economic viability of NW-based solar cells. Here, we demonstrate a simple, low-cost, and scalable route to dramatically enhance the optical antenna effect in NW photovoltaic devices by coating the wires with conformal dielectric shells. Scattering and absorption measurements on Si NWs coated with shells of SiNx or SiOx exhibit a broadband enhancement of light absorption by ∼50-200% and light scattering by ∼200-1000%. The increased light-matter interaction leads to a ∼80% increase in short-circuit current density in Si photovoltaic devices under 1 sun illumination. Optical simulations reproduce the experimental results and indicate the dielectric-shell effect to be a general phenomenon for groups IV, II-VI, and III-V semiconductor NWs in both lateral and vertical orientations, providing a simple route to approximately double the efficiency of NW-based solar cells.

Original languageEnglish
Pages (from-to)753-758
Number of pages6
JournalNano Letters
Issue number1
Publication statusPublished - 2015 Jan 14


  • FDTD simulation
  • Solar energy
  • optical antenna
  • photovoltaic device
  • silicon nanowires

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


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