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Minkov D, Angelov G, Marquez E, Radonov R, Rusev R, Nikolov D, Ruano S. Increasing the Accuracy of the Characterization of a Thin Semiconductor or Dielectric Film on a Substrate from Only One Quasi-Normal Incidence UV/Vis/NIR Reflectance Spectrum of the Sample. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2407. [PMID: 37686915 PMCID: PMC10489747 DOI: 10.3390/nano13172407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/13/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023]
Abstract
OEMT is an existing optimizing envelope method for thin-film characterization that uses only one transmittance spectrum, T(λ), of the film deposited on the substrate. OEMT computes the optimized values of the average thickness, d¯, and the thickness non-uniformity, Δd, employing variables for the external smoothing of T(λ), the slit width correction, and the optimized wavelength intervals for the computation of d¯ and Δd, and taking into account both the finite size and absorption of the substrate. Our group had achieved record low relative errors, <0.1%, in d¯ of thin semiconductor films via OEMT, whereas the high accuracy of d¯ and Δd allow for the accurate computation of the complex refractive index, N˙(λ), of the film. In this paper is a proposed envelope method, named OEMR, for the characterization of thin dielectric or semiconductor films using only one quasi-normal incidence UV/Vis/NIR reflectance spectrum, R(λ), of the film on the substrate. The features of OEMR are similar to the described above features of OEMT. OEMR and several popular dispersion models are employed for the characterization of two a-Si films, only from R(λ), with computed d¯ = 674.3 nm and Δd = 11.5 nm for the thinner film. It is demonstrated that the most accurate characterizations of these films over the measured spectrum are based on OEMR.
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Affiliation(s)
- Dorian Minkov
- Scientific Research Section (NIS), Technical University, 1000 Sofia, Bulgaria
| | - George Angelov
- Department of Microelectronics, Faculty of Electronics Engineering and Technologies, Technical University, 1000 Sofia, Bulgaria; (G.A.); (R.R.); (R.R.); (D.N.)
| | - Emilio Marquez
- Faculty of Science, Department of Condensed-Matter Physics, University of Cadiz, Puerto Real, 11510 Cadiz, Spain;
| | - Rossen Radonov
- Department of Microelectronics, Faculty of Electronics Engineering and Technologies, Technical University, 1000 Sofia, Bulgaria; (G.A.); (R.R.); (R.R.); (D.N.)
| | - Rostislav Rusev
- Department of Microelectronics, Faculty of Electronics Engineering and Technologies, Technical University, 1000 Sofia, Bulgaria; (G.A.); (R.R.); (R.R.); (D.N.)
| | - Dimitar Nikolov
- Department of Microelectronics, Faculty of Electronics Engineering and Technologies, Technical University, 1000 Sofia, Bulgaria; (G.A.); (R.R.); (R.R.); (D.N.)
| | - Susana Ruano
- Photovoltaic Solar Energy Unit, Centre for Energy, Environmental and Technological Research (CIEMAT), Avenida Complutense 40, 28040 Madrid, Spain;
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Polarization Control in Integrated Silicon Waveguides Using Semiconductor Nanowires. NANOMATERIALS 2022; 12:nano12142438. [PMID: 35889662 PMCID: PMC9320397 DOI: 10.3390/nano12142438] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/09/2022] [Accepted: 07/12/2022] [Indexed: 01/27/2023]
Abstract
In this work, we show the design of a silicon photonic-based polarization converting device based on the integration of semiconduction InP nanowires on the silicon photonic platform. We present a comprehensive numerical analysis showing that full polarization conversion (from quasi-TE modes to quasi-TM modes, and vice versa) can be achieved in devices exhibiting small footprints (total device lengths below 20 µm) with minimal power loss (<2 dB). The approach described in this work can pave the way to the realization of complex and re-configurable photonic processors based on the manipulation of the state of polarization of guided light beams.
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Zagaglia L, Demontis V, Rossella F, Floris F. Particle swarm optimization of GaAs-AlGaAS nanowire photonic crystals as two-dimensional diffraction gratings for light trapping. NANO EXPRESS 2022. [DOI: 10.1088/2632-959x/ac61ec] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Abstract
Semiconductor nanowire ordered arrays represent a class of bi-dimensional photonic crystals that can be engineered to obtain functional metamaterials. Here is proposed a novel approach, based on a particle swarm optimization algorithm, for using such a photonic crystal concept to design a semiconductor nanowire-based two-dimensional diffraction grating able to guarantee an in-plane coupling for light trapping. The method takes into account the experimental constraints associated to the bottom-up growth of nanowire arrays, by processing as input dataset all relevant geometrical and morphological features of the array, and returns as output the optimised set of parameters according to the desired electromagnetic functionality of the metamaterial. A case of study based on an array of tapered GaAs-AlGaAs core-shell nanowire heterostructures is discussed.
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Demontis V, Zannier V, Sorba L, Rossella F. Surface Nano-Patterning for the Bottom-Up Growth of III-V Semiconductor Nanowire Ordered Arrays. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2079. [PMID: 34443910 PMCID: PMC8398085 DOI: 10.3390/nano11082079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 12/18/2022]
Abstract
Ordered arrays of vertically aligned semiconductor nanowires are regarded as promising candidates for the realization of all-dielectric metamaterials, artificial electromagnetic materials, whose properties can be engineered to enable new functions and enhanced device performances with respect to naturally existing materials. In this review we account for the recent progresses in substrate nanopatterning methods, strategies and approaches that overall constitute the preliminary step towards the bottom-up growth of arrays of vertically aligned semiconductor nanowires with a controlled location, size and morphology of each nanowire. While we focus specifically on III-V semiconductor nanowires, several concepts, mechanisms and conclusions reported in the manuscript can be invoked and are valid also for different nanowire materials.
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Affiliation(s)
- Valeria Demontis
- NEST, Scuola Normale Superiore and Istituto Nanoscienze CNR, Piazza S. Silvestro 12, 56127 Pisa, Italy; (V.Z.); (L.S.)
| | - Valentina Zannier
- NEST, Scuola Normale Superiore and Istituto Nanoscienze CNR, Piazza S. Silvestro 12, 56127 Pisa, Italy; (V.Z.); (L.S.)
| | - Lucia Sorba
- NEST, Scuola Normale Superiore and Istituto Nanoscienze CNR, Piazza S. Silvestro 12, 56127 Pisa, Italy; (V.Z.); (L.S.)
| | - Francesco Rossella
- NEST, Scuola Normale Superiore and Istituto Nanoscienze CNR, Piazza S. Silvestro 12, 56127 Pisa, Italy; (V.Z.); (L.S.)
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy
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Raad SH, Atlasbaf Z. Solar cell design using graphene-based hollow nano-pillars. Sci Rep 2021; 11:16169. [PMID: 34373553 PMCID: PMC8352917 DOI: 10.1038/s41598-021-95684-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 07/26/2021] [Indexed: 02/07/2023] Open
Abstract
In this paper, the full solar spectrum coverage with an absorption efficiency above 96% is attained by shell-shaped graphene-based hollow nano-pillars on top of the refractory metal substrate. The material choice guarantees the high thermal stability of the device along with its robustness against harsh environmental conditions. To design the structure, constitutive parameters of graphene material in the desired frequency range are investigated and its absorption capability is illustrated by calculating the attenuation constant of the electromagnetic wave. It is observed that broadband absorption is a consequence of wideband retrieved surface impedance matching with the free-space intrinsic impedance due to the tapered geometry. Moreover, the azimuthal and longitudinal cavity resonances with different orders are exhibited for a better understanding of the underlying wideband absorption mechanism. Importantly, the device can tolerate the oblique incidence in a wide span around 65°, regardless of the polarization. The proposed structure can be realized by large-area fabrication techniques.
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Affiliation(s)
- Shiva Hayati Raad
- Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, Iran.
| | - Zahra Atlasbaf
- Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, Iran
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Zagaglia L, Demontis V, Rossella F, Floris F. Semiconductor nanowire arrays for optical sensing: a numerical insight on the impact of array periodicity and density. NANOTECHNOLOGY 2021; 32:335502. [PMID: 33971637 DOI: 10.1088/1361-6528/abff8b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/10/2021] [Indexed: 06/12/2023]
Abstract
Recent advances in the nanofabrication and modeling of metasurfaces have shown the potential of these systems in providing unprecedented control over light-matter interactions at the nanoscale, enabling immediate and tangible improvement of features and specifications of photonic devices that are becoming always more crucial in enhancing everyday life quality. In this work, we theoretically demonstrate that metasurfaces made of periodic and non-periodic deterministic assemblies of vertically aligned semiconductor nanowires can be engineered to display a tailored effective optical response and provide a suitable route to realize advanced systems with controlled photonic properties particularly interesting for sensing applications. The metasurfaces investigated in this paper correspond to nanowire arrays that can be experimentally realized exploiting nanolithography and bottom-up nanowire growth methods: the combination of these techniques allow to finely control the position and the physical properties of each individual nanowire in complex arrays. By resorting to numerical simulations, we address the near- and far-field behavior of a nanowire ensemble and we show that the controlled design and arrangement of the nanowires on the substrate may introduce unprecedented oscillations of light reflectance, yielding a metasurface which displays an electromagnetic behavior with great potential for sensing. Finite-difference time-domain numerical simulations are carried out to tailor the nanostructure parameters and systematically engineer the optical response in the VIS-NIR spectral range. By exploiting our computational-methods we set-up a complete procedure to design and test metasurfaces able to behave as functional sensors. These results are especially encouraging in the perspective of developing arrays of epitaxially grown semiconductor nanowires, where the suggested design can be easily implemented during the nanostructure growth, opening the way to fully engineered nanowire-based optical metamaterials.
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Affiliation(s)
- Luca Zagaglia
- Tyndall National Institute, University College Cork, Cork, Ireland
| | - Valeria Demontis
- NEST Laboratory, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy
| | - Francesco Rossella
- NEST Laboratory, Scuola Normale Superiore and Istituto Nanoscienze-CNR, Pisa, Italy
| | - Francesco Floris
- Tyndall National Institute, University College Cork, Cork, Ireland
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Petronijevic E, Belardini A, Leahu G, Hakkarainen T, Piton MR, Koivusalo E, Sibilia C. Broadband optical spin dependent reflection in self-assembled GaAs-based nanowires asymmetrically hybridized with Au. Sci Rep 2021; 11:4316. [PMID: 33619343 PMCID: PMC7900205 DOI: 10.1038/s41598-021-83899-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 12/29/2020] [Indexed: 11/09/2022] Open
Abstract
Hybridization of semiconductor nanostructures with asymmetric metallic layers offers new paths to circular polarization control and chiral properties. Here we study, both experimentally and numerically, chiral properties of GaAs-based nanowires (NWs) which have two out of six sidewalls covered by Au. Sparse ensembles of vertical, free-standing NWs were fabricated by means of lithography-free self-assembled technique on Si substrates and subsequently covered by Au using tilted evaporation. We report on optical spin-dependent specular reflection in the 680–1000 nm spectral range when the orientation of the golden layers follows the rule of extrinsic chirality. The analysis shows reflection peaks of the chiral medium whose intensity is dependent on the light handedness. We further propose a novel, time-efficient numerical method that enables a better insight into the far-field intensity and distribution of the scattered light from a sparse NW ensembles. The measurements done on three different samples in various orientations show good agreement with theoretical predictions over a broad wavelength range.
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Affiliation(s)
- Emilija Petronijevic
- Dipartimento di Scienze di Base ed Applicate per l'Ingegneria, Sapienza Università di Roma, Via A. Scarpa 16, 00161, Rome, Italy.
| | - Alessandro Belardini
- Dipartimento di Scienze di Base ed Applicate per l'Ingegneria, Sapienza Università di Roma, Via A. Scarpa 16, 00161, Rome, Italy
| | - Grigore Leahu
- Dipartimento di Scienze di Base ed Applicate per l'Ingegneria, Sapienza Università di Roma, Via A. Scarpa 16, 00161, Rome, Italy
| | - Teemu Hakkarainen
- Dipartimento di Scienze di Base ed Applicate per l'Ingegneria, Sapienza Università di Roma, Via A. Scarpa 16, 00161, Rome, Italy.,Optoelectronics Research Centre, Physics Unit, Tampere University, Korkeakoulunkatu 3, 33720, Tampere, Finland
| | - Marcelo Rizzo Piton
- Optoelectronics Research Centre, Physics Unit, Tampere University, Korkeakoulunkatu 3, 33720, Tampere, Finland
| | - Eero Koivusalo
- Optoelectronics Research Centre, Physics Unit, Tampere University, Korkeakoulunkatu 3, 33720, Tampere, Finland
| | - Concita Sibilia
- Dipartimento di Scienze di Base ed Applicate per l'Ingegneria, Sapienza Università di Roma, Via A. Scarpa 16, 00161, Rome, Italy
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Liu W, Wang Y, Guo X, Song J, Wang X, Yi Y. Light Trapping in Single Elliptical Silicon Nanowires. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:nano10112121. [PMID: 33113822 PMCID: PMC7692122 DOI: 10.3390/nano10112121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 06/11/2023]
Abstract
Light trapping in single nanowires (NWs) is of vital importance for photovoltaic applications. However, circular NWs (CNWs) can limit their light-trapping ability due to high geometrical symmetry. In this work, we present a detailed study of light trapping in single silicon NWs with an elliptical cross-section (ENWs). We demonstrate that the ENWs exhibit significantly enhanced light trapping compared with the CNWs, which can be ascribed to the symmetry-broken structure that can orthogonalize the direction of light illumination and the leaky mode resonances (LMRs). That is, the elliptical cross-section can simultaneously increase the light path length by increasing the vertical axis and reshape the LMR modes by decreasing the horizontal axis. We found that the light absorption can be engineered via tuning the horizontal and vertical axes, the photocurrent is significantly enhanced by 374.0% (150.3%, 74.1%) or 146.1% (61.0%, 35.3%) in comparison with that of the CNWs with the same diameter as the horizontal axis of 100 (200, 400) nm or the vertical axis of 1000 nm, respectively. This work advances our understanding of how to improve light trapping based on the symmetry breaking from the CNWs to ENWs and provides a rational way for designing high-efficiency single NW photovoltaic devices.
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Affiliation(s)
- Wenfu Liu
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian, Henan 463000, China; (Y.W.); (X.G.); (J.S.)
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA;
| | - Yinling Wang
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian, Henan 463000, China; (Y.W.); (X.G.); (J.S.)
| | - Xiaolei Guo
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian, Henan 463000, China; (Y.W.); (X.G.); (J.S.)
| | - Jun Song
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian, Henan 463000, China; (Y.W.); (X.G.); (J.S.)
| | - Xiao Wang
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA;
| | - Yasha Yi
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA;
- Energy Institute, University of Michigan, Ann Arbor, MI 48109, USA
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9
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Liu W, Guo X, Xing S, Yao H, Wang Y, Bai L, Wang Q, Zhang L, Wu D, Zhang Y, Wang X, Yi Y. Off-Resonant Absorption Enhancement in Single Nanowires via Graded Dual-Shell Design. NANOMATERIALS 2020; 10:nano10091740. [PMID: 32887500 PMCID: PMC7559431 DOI: 10.3390/nano10091740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 01/04/2023]
Abstract
Single nanowires (NWs) are of great importance for optoelectronic applications, especially solar cells serving as powering nanoscale devices. However, weak off-resonant absorption can limit its light-harvesting capability. Here, we propose a single NW coated with the graded-index dual shells (DSNW). We demonstrate that, with appropriate thickness and refractive index of the inner shell, the DSNW exhibits significantly enhanced light trapping compared with the bare NW (BNW) and the NW only coated with the outer shell (OSNW) and the inner shell (ISNW), which can be attributed to the optimal off-resonant absorption mode profiles due to the improved coupling between the reemitted light of the transition modes of the leak mode resonances of the Si core and the nanofocusing light from the dual shells with the graded refractive index. We found that the light absorption can be engineered via tuning the thickness and the refractive index of the inner shell, the photocurrent density is significantly enhanced by 134% (56%, 12%) in comparison with that of the BNW (OSNW, ISNW). This work advances our understanding of how to improve off-resonant absorption by applying graded dual-shell design and provides a new choice for designing high-efficiency single NW photovoltaic devices.
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Affiliation(s)
- Wenfu Liu
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
- Correspondence: (W.L.); (Y.Y.)
| | - Xiaolei Guo
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Shule Xing
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Haizi Yao
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Yinling Wang
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Liuyang Bai
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Qi Wang
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Liang Zhang
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Dachuan Wu
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
| | - Yuxiao Zhang
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
| | - Xiao Wang
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
| | - Yasha Yi
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
- Energy Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Correspondence: (W.L.); (Y.Y.)
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