Omnidirectional Near-Unity Absorption in an Ultrathin Planar Semiconductor Layer on a Metal Substrate
- Authors
- Park, Junghyun; Kang, Ju-Hyung; Vasudev, Alok P.; Schoen, David T.; Kim, Hwi; Hasman, Erez; Brongersma, Mark L.
- Issue Date
- 9월-2014
- Publisher
- AMER CHEMICAL SOC
- Keywords
- optical absorption; perfect absorber; semiconductor; surface plasmon polariton; critical coupling
- Citation
- ACS PHOTONICS, v.1, no.9, pp.812 - 821
- Indexed
- SCIE
SCOPUS
- Journal Title
- ACS PHOTONICS
- Volume
- 1
- Number
- 9
- Start Page
- 812
- End Page
- 821
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/97536
- DOI
- 10.1021/ph500093d
- ISSN
- 2330-4022
- Abstract
- We present omnidirectional near-unity absorption of light in an ultrathin planar semiconductor layer on a metal substrate. Using full-field simulations and a modal analysis, it is shown that more than 98% of the incident light energy can be absorbed in a mere 12 nm thick Ge layer on a Ag substrate at the wavelength of 625 nm over a wide range of angles (80% absorption up to 66 degrees in the transverse magnetic and 67 degrees in the transverse electric polarizations). The physical origin of such remarkable absorption properties is the coupling of incident light to the Brewster mode supported by the structure. The modal dispersion connects several critical coupling points in a dispersion diagram at which the absorption is unity and exhibits a virtually flat dispersion relation for both polarizations, resulting in omnidirectional, near-unity absorption. Potential applications of this simple, planar geometry such as photodetectors and solar cells made from various semiconductor materials are also discussed along with feasible charge-extracting structures and performance estimates.
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Collections - Graduate School > Department of Electronics and Information Engineering > 1. Journal Articles
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