Creating semiconductor metafilms with designer absorption spectra

Soo Jin Kim, Pengyu Fan, Ju Hyung Kang, Mark L. Brongersma

Research output: Contribution to journalArticlepeer-review

75 Citations (Scopus)


The optical properties of semiconductors are typically considered intrinsic and fixed. Here we leverage the rapid developments in the field of optical metamaterials to create ultrathin semiconductor metafilms with designer absorption spectra. We show how such metafilms can be constructed by placing one or more types of high-index semiconductor antennas into a dense array with subwavelength spacings. It is argued that the large absorption cross-section of semiconductor antennas and their weak near-field coupling open a unique opportunity to create strongly absorbing metafilms whose spectral absorption properties directly reflect those of the individual antennas. Using experiments and simulations, we demonstrate that near-unity absorption at one or more target wavelengths of interest can be achieved in a sub-50-nm-thick metafilm using judiciously sized and spaced Ge nanobeams. The ability to create semiconductor metafilms with custom absorption spectra opens up new design strategies for planar optoelectronic devices and solar cells.

Original languageEnglish
Article number7591
JournalNature communications
Publication statusPublished - 2015 Jul 17
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2015 Macmillan Publishers Limited. All rights reserved.

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry,Genetics and Molecular Biology
  • General Physics and Astronomy


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