Creating semiconductor metafilms with designer absorption spectra
- Geballe Lab for Advanced Materials, Stanford, CA (United States); California Institute of Technology
- Geballe Lab for Advanced Materials, Stanford, CA (United States)
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. Furthermore, the ability to create semiconductor metafilms with custom absorption spectra opens up new design strategies for planar optoelectronic devices and solar cells.
- Research Organization:
- California Inst. of Technology (CalTech), Pasadena, CA (United States); Energy Frontier Research Centers (EFRC) (United States). Light-Material Interactions in Energy Conversion (LMI)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- SC0001293
- OSTI ID:
- 1459205
- Journal Information:
- Nature Communications, Journal Name: Nature Communications Journal Issue: 1 Vol. 6; ISSN 2041-1723
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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