Highly Efficient Semiconductor-Based Metasurface for Photoelectrochemical Water Splitting: Broadband Light Perfect Absor
- PDF / 2,472,451 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 40 Downloads / 249 Views
Highly Efficient Semiconductor-Based Metasurface for Photoelectrochemical Water Splitting: Broadband Light Perfect Absorption with Dimensions Smaller than the Diffusion Length Amir Ghobadi 1,2,3
&
Turkan Gamze Ulusoy Ghobadi 1,4,5 & Ferdi Karadas 1,6 & Ekmel Ozbay 1,2,3,7
Received: 12 September 2019 / Accepted: 4 December 2019 # Springer Science+Business Media, LLC, part of Springer Nature 2019
Abstract In this paper, we demonstrate a highly efficient light trapping design that is made of a metal-oxide-semiconductor-semiconductor (nanograting/nanopatch) (MOSSg/p) four-layer design to absorb light in a broad wavelength regime in dimensions smaller than the hole diffusion length of the active layer. For this aim, we first adopt a modeling approach based on the transfer matrix method (TMM) to find out the absorption bandwidth (BW) limits of a simple hematite (α-Fe2O3)-based metal-oxide-semiconductor (MOS) cavity design. Our modeling findings show that this design architecture can provide near-perfect absorption in shorter wavelengths. To extend the absorption toward longer wavelengths, a nanostructured semiconductor is placed on top of this MOS design. This nanostructure supports the Mie resonance and adds a new resonance in longer wavelengths without disrupting the lower wavelength absorption capability of MOS cavity. By this way, a polarization-insensitive absorption above 0.8 can be acquired up to λ=565 nm. Moreover, to have a better qualitative comparison, the water-splitting photocurrent of this design has been estimated. Our calculations show that a photocurrent as high as 10.6 mA cm−2 can be achieved with this design that is quite close to the theoretical limit of 12.5 mA cm−2 for hematite-based water-splitting photoanode. This paper proposes a design approach in which the superposition of cavity modes and Mie resonances can lead to a broadband, polarization-insensitive, and omnidirectional near-perfect light absorption in dimensions smaller than the carrier’s diffusion length. This can be considered as a winning strategy to design highly efficient and ultrathin optoelectronic designs in a variety of applications including photoelectrochemical water splitting and photovoltaics. Keywords Metamaterials . Semiconductor metasurfaces . Perfect absorber . Plasmonics . Photochemistry . Light-driven water splitting
Introduction * Amir Ghobadi [email protected] 1
UNAM–National Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey
2
NANOTAM - Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey
3
Department of Electrical and Electronics Engineering, Bilkent University, 06800 Ankara, Turkey
4
Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
5
Department of Energy Engineering, Faculty of Engineering, Ankara University, 06830 Ankara, Turkey
6
Department of Chemistry, Bilkent University, 06800 Ankara, Turkey
7
Department of Physics, Bilkent University, 06800 Ankara, Turkey
The concept of metamaterials and metasurfaces
Data Loading...
