Patrick RUFANGURA | University of Technology Sydney (original) (raw)
Papers by Patrick RUFANGURA
Global adoption of solar photovoltaic (PV) cells as a sustainable substitute to fossil fuel techn... more Global adoption of solar photovoltaic (PV) cells as a sustainable substitute to fossil fuel technologies has been impeded by its low efficiency. Generally, efficiency of these devices strongly depends on their ability to absorb radiations of electromagnetic waves incident on them. Their low absorptivity provides a challenge. Metamaterials (MTM) based solar cells offer an opportunity for increasing the system efficiency by enhancing the total absorbed solar radiation incident on solar PV cells. In this thesis a wide-band MTM absorber for solar cell application is proposed. The thesis first explains theories, properties and applications of metamaterials. Different absorber designs, including dual-bands and tunable wide-band perfect MTMs, are then proposed, characterized and numerically discussed. Absorption rates of more than 99% are numerically achieved for all the presented designs. Furthermore, a novel absorber is proposed, where a nearly perfect absorption is gained with a wide-ba...
Body: Surface plasmon polariton (SPP), which result from the strong coupling of bound electromagn... more Body: Surface plasmon polariton (SPP), which result from the strong coupling of bound electromagnetic (EM) waves and collective charge oscillations, enable subwavelength manipulation of light and matter interaction. Conventional noble metals-based SPP excited in the visible and near-Infrared spectra ranges suffer from large energy losses and cannot be dynamically tuned. Thanks to its 2D nature, graphene has emerged as a promising alternative plasmonic material with well- confined SPPs in the mid-infrared (MIR) and terahertz (THz) ranges and remarkable tunability. On the other hand, polar dielectric materials support low optical losses and sub-wavelength mode in the MIR and THz regions via surface phonon polariton (SPhP)mode' stimulation within the Reststrahlen band, a narrow spectral range between transverse optical (TO) and longitudinal optical (LO) frequencies. Due to the excellent polaritonic responses in both graphene and silicon carbide in the MIR and THz regions, devices c...
Within the past decades, flooding has become a global pandemic, which hampers economic and social... more Within the past decades, flooding has become a global pandemic, which hampers economic and social development. This global phenomenon has led to loss of lives and economic damages in many countries including Ghana. On June 3rd 2015, Accra, Ghana's capital experienced an unprecedented flash flood event, coupled with an explosion at a Goil filling station that resulted in a death toll of over 152 lives. It is therefore necessary to explore new ideas and approaches that can be incorporated to existing structures to manage this problem. The aim of this study is to analyse the underlying causes of flood in Accra, examine the suitable structural measures that can be undertaken to mitigate flood impacts in Accra, and propose a mitigation approach to manage flood impacts using Integrated Flood Risk Management and Sustainable Flood Management. The Intensity of rainfall events in eight drainage basins in Accra namely; Kpeshie, Korle, Densu, Sakumo, Lafa, Osu, Songo Mokwe and Chemu trigger...
Nanomaterials, 2021
The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational... more The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational fingerprints. There is a growing interest in nanophotonics operating in this spectral range, and recent advances in plasmonic research are aimed at enhancing MIR infrared nanophotonics. In particular, the design of hybrid plasmonic metasurfaces has emerged as a promising route to realize novel MIR applications. Here we demonstrate a hybrid nanostructure combining graphene and silicon carbide to extend the spectral phonon response of silicon carbide and enable absorption and field enhancement of the MIR photon via the excitation and hybridization of surface plasmon polaritons and surface phonon polaritons. We combine experimental methods and finite element simulations to demonstrate enhanced absorption of MIR photons and the broadening of the spectral resonance of graphene-coated silicon carbide nanowires. We also indicate subwavelength confinement of the MIR photons within a thin oxide ...
Journal of Physics: Materials, 2020
The ability to control the interaction of light and matter at the nanoscale is at the heart of th... more The ability to control the interaction of light and matter at the nanoscale is at the heart of the field of nanophotonics. This subdiffractional confinement of light can be achieved through the stimulation of surface polaritons, most notably surface plasmon polaritons (SPPs). However, the high optical losses and lack of tunability of conventional plasmonic materials have hindered major progress in this field. In the search for alternative low-loss and tunable materials, graphene and polar dielectric materials are viewed as potential alternatives to more common metal-based plasmonic materials. In particular, the possibility of combining the tunable nature of graphene SPPs with the high-quality factors and long lifetimes of surface phonon-polaritons (SPhPs) modes supported in polar dielectric materials (e.g. SiC) offers great promise for advanced nanophotonic applications. The combination of graphene SPPs and SPhPs supported in SiC is even more pertinent as this material system can be...
Journal of Nanophotonics, 2018
The current state of energy is characterized by complex challenges in production processes and en... more The current state of energy is characterized by complex challenges in production processes and environmental issues. With the world population continuing to multiply faster and the globalization process, additional energy production is needed to meet future demands. Solar energy is one of the best sustainable energy resources, which is expected to play a vital role in this scenario. One of the best techniques to harvest this resource is through solar photovoltaic technology, which produces electricity directly from solar radiation. But, one of the problems still persisting is its low efficiency. To harness this technology, this problem needs to be addressed. Metamaterial (MTM) technology has enabled the creation of advanced devices for various applications. Solar cell technology is one of the fields to benefit from this technology. MTM perfect absorber can be used in solar cells to improve their absorption. Multiple-bands MTM absorber for next generation high-efficiency solar cells is proposed. The design gives a nearly perfect absorption (99.94%) with a bandwidth of 23.4% in visible spectrum. In addition, the geometric flexibility of a proposed design causes its absorption rate to be insensitive of polarization angles and angles of incident electromagnetic radiations.
Applied Physics A, 2016
This paper suggests a metamaterial (MTM) absorber structure to be used for efficiency improved so... more This paper suggests a metamaterial (MTM) absorber structure to be used for efficiency improved solar cell. The proposed MTM absorber consists of the topmost three concentric circular ring resonators, and a ground metal plane sandwiched to the top layer with a dielectric spacer. Numerical simulation and theoretical (interference theory) studies on the proposed design show a wideband with near-perfect (>99%) absorption response in the visible frequency region of the solar spectrum. Thermal characterization of the suggested design is also conducted in order to investigate its absorption capability at different temperatures. The proposed MTM absorber design is believed to be an outstanding candidate toward high-efficiency solar photovoltaic cell.
Journal of Alloys and Compounds, 2016
Since the discovery of metamaterial absorber to the present days, several designs were proposed w... more Since the discovery of metamaterial absorber to the present days, several designs were proposed which display single-, dual-, and multiple-bands absorption responses in almost all regions of solar spectrum. However, little work has been done for wide-band metamaterial absorber in the visible frequency range. Hence, a novel wide-band metamaterial perfect absorber (MPA) based on concentric Circular Ring Resonator (CRR) topology is proposed for the application to improve the absorbance of solar photovoltaic cells for the visible frequency region. The proposed design consists of three basic components as resonators, ground metal, and dielectric spacer. The geometrical parametric study is conducted in order to investigate the flexibility of the proposed MPA structure. The design flexibility also analyzed by the polarization angle insensitivity character, in which the proposed design provides the perfect absorption for different angles of the incident electromagnetic wave as well as for TE and TM polarized waves.
Journal of Alloys and Compounds, 2016
This paper proposes a metamaterial absorber design for solar energy harvesting using a simplified... more This paper proposes a metamaterial absorber design for solar energy harvesting using a simplified and symmetric structure. A unit cell of this design consists of three important layers namely, the bottom metallic layer, which is gold lossy, the intermediate layer: made of a lossy dielectric material that is gallium arsenide and patches which formed by a combination of gold and gallium arsenide. These three important layers are being carefully arranged at the top of a dielectric spacer. The geometric structure was being examined for its contribution towards absorption characteristics. The simulation results show outstanding dual-bands absorption (99.96% and 99.37%) in the visible frequency regime of electromagnetic wave. Due to the excellent symmetric nature of the proposed structure, its absorptance capacity exhibits polarization insensitivity for a wide range of incident angles for electromagnetic radiation.
physica status solidi (c), 2015
A metamaterial absorber that effectively harvests solar energy is being proposed in this paper us... more A metamaterial absorber that effectively harvests solar energy is being proposed in this paper using a simple and high flexible structure. The proposed structure unit cell comprises of three vital layers. The ground metallic plane, an intermediate dielectric spacer while patches are wisely prepared on the top of a dielectric spacer. Geometrical parameters of the proposed metamaterial is studied in order to get insight on their impact for the absorption behaviour of the structure. The results from simulation provides two excellent absorption resonance (99.96% and 99.37%) in the visible spectrum range of electromagnetic wave. Due to the excellent symmetry of the proposed metamaterial design, its absorption coefficient is polarisation insensitive for a wide range of incident angles of electromagnetic radiations.
IET Optoelectronics, 2016
Developing a perfect absorber based on metamaterials (MTMs) is a promising technique towards impr... more Developing a perfect absorber based on metamaterials (MTMs) is a promising technique towards improving the efficiency of solar photovoltaic cells. In this study, a novel MTM-based perfect absorber (MPA) is proposed for solar cell applications, which exhibits an excellent single-band with high absorption rate of 99.7% in visible frequency regime (resonance frequency of 614.4 THz) with an outstanding absorption bandwidth of 15.5%. The proposed design presents a high symmetry flexibility which makes it easy to fabricate. Besides, the simulation results for the defined different incident angles and different polarisation (transverse electric and transverse magnetic) confirm the quality of the proposed design by showing how insensitive it is to both the defined incident angles (normal and oblique incident) and different polarisation angles of electromagnetic wave. The parametric study on dielectric spacer shows the tunability characteristic of an intended MPA structure. The proposed MPA design is a good candidate for fabrication of high-efficiency solar cell operating in a visible frequency range.
The mid-infrared optical spectrum hosts a variety of promising photonic applications. Herein we s... more The mid-infrared optical spectrum hosts a variety of promising photonic applications. Herein we simulate and experimentally demonstrate reflectance enhancement of MIR light using graphene-coated silicon carbide nanowires on silicon, showing promise for on-chip MIR Nano photonics.
Nanomaterials
The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational... more The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational fingerprints. There is a growing interest in nanophotonics operating in this spectral range, and recent advances in plasmonic research are aimed at enhancing MIR infrared nanophotonics. In particular, the design of hybrid plasmonic metasurfaces has emerged as a promising route to realize novel MIR applications. Here we demonstrate a hybrid nanostructure combining graphene and silicon carbide to extend the spectral phonon response of silicon carbide and enable absorption and field enhancement of the MIR photon via the excitation and hybridization of surface plasmon polaritons and surface phonon polaritons. We combine experimental methods and finite element simulations to demonstrate enhanced absorption of MIR photons and the broadening of the spectral resonance of graphene-coated silicon carbide nanowires. We also indicate subwavelength confinement of the MIR photons within a thin oxide ...
Enhanced Absorption with Graphene-Coated Silicon Carbide Nanowires for Mid-Infrared Nanophotonics, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
ABSTRACT The efficiency of photovoltaic cells (PV) has been one of the major problem impeding its... more ABSTRACT The efficiency of photovoltaic cells (PV) has been one of the major problem impeding its global adoption as a sustainable substitute to fossil fuel based technologies. Metamaterials (MTM) based solar cells offers a unique opportunity towards increasing the system efficiency by enhancing the total absorbed solar radiation incident on this device. In this study, a nanostructure based MTM perfect absorber has been designed and simulated. By adjusting geometrical parameters and MTM properties of the structure, nearly perfect dual-band resonances were obtained. The two bands peaked at 524.5 THz and 655 THz with corresponding absorption of 99.99 % and 99.8 %, respectively. The proposed structure is simple and more flexible for adjustment, which help to achievement of multiple and wide bands. Implementation of the designed structure can effectively lead to the realization of more efficiency PV solar cells.
Journal of Nanophotonics
A wideband metamaterial (MTM) absorber based on a concentric ring resonator is discussed at visib... more A wideband metamaterial (MTM) absorber based on a concentric ring resonator is discussed at visible frequencies. The proposed structure offers a wideband absorption response, where absorption of >70% is gained for the frequency ranging from 537.91 to 635.73 THz. The analysis is conducted on the components of the proposed structure to understand the origin of wideband absorption. Furthermore, a graphene monolayer sheet is integrated to the proposed MTM absorber to optimize its absorptivity, where the studies show enhancement of the absorptivity of the proposed structure up to 26% from its initial absorptivity. MTM absorbers of this kind have potential applications in solar cells.
Journal of Physics: Materials, 2020
The ability to control the interaction of light and matter at the nanoscale is at the heart of th... more The ability to control the interaction of light and matter at the nanoscale is at the heart of the field of nanophotonics. This subdiffractional confinement of light can be achieved through the stimulation of surface polaritons, most notably surface plasmon polaritons (SPPs). However, the high optical losses and lack of tunability of conventional plasmonic materials have hindered major progress in this field. In the search for alternative low-loss and tunable materials, graphene and polar dielectric materials are viewed as potential alternatives to more common metal-based plasmonic materials. In particular, the possibility of combining the tunable nature of graphene SPPs with the high-quality factors and long lifetimes of surface phonon-polaritons (SPhPs) modes supported in polar dielectric materials (e.g., SiC) offers great promise for advanced nanophotonic applications. The combination of graphene SPPs and SPhPs supported in SiC is even more pertinent as this material system can be realized in the form of epitaxial graphene (EG), whereby sublimation of silicon from a SiC results in a surface reconstruction into a graphene surface termination. This offers an ideal technology platform for realizing hybrid SPP-SPhP modes. In this review, we outline advances in graphene plasmonics and the generation of SPhPs in polar materials, in the context of epitaxial graphene. We review recent attempts at realizing such coupling of graphene SPPs with phonon and SPhP modes in SiC, as well as covering such modes in other polar materials and conclude with an overview of advantages and challenges for further advancement of nanophotonics based on graphene on silicon carbide for on-chip light manipulation.
Patrick Rufangura, Cumali Sabah, "Perfect metamaterial absorber for applications in sustainable a... more Patrick Rufangura, Cumali Sabah, "Perfect metamaterial absorber for applications in sustainable and highefficiency solar cells,"
Global adoption of solar photovoltaic (PV) cells as a sustainable substitute to fossil fuel techn... more Global adoption of solar photovoltaic (PV) cells as a sustainable substitute to fossil fuel technologies has been impeded by its low efficiency. Generally, efficiency of these devices strongly depends on their ability to absorb radiations of electromagnetic waves incident on them. Their low absorptivity provides a challenge. Metamaterials (MTM) based solar cells offer an opportunity for increasing the system efficiency by enhancing the total absorbed solar radiation incident on solar PV cells. In this thesis a wide-band MTM absorber for solar cell application is proposed. The thesis first explains theories, properties and applications of metamaterials. Different absorber designs, including dual-bands and tunable wide-band perfect MTMs, are then proposed, characterized and numerically discussed. Absorption rates of more than 99% are numerically achieved for all the presented designs. Furthermore, a novel absorber is proposed, where a nearly perfect absorption is gained with a wide-ba...
Body: Surface plasmon polariton (SPP), which result from the strong coupling of bound electromagn... more Body: Surface plasmon polariton (SPP), which result from the strong coupling of bound electromagnetic (EM) waves and collective charge oscillations, enable subwavelength manipulation of light and matter interaction. Conventional noble metals-based SPP excited in the visible and near-Infrared spectra ranges suffer from large energy losses and cannot be dynamically tuned. Thanks to its 2D nature, graphene has emerged as a promising alternative plasmonic material with well- confined SPPs in the mid-infrared (MIR) and terahertz (THz) ranges and remarkable tunability. On the other hand, polar dielectric materials support low optical losses and sub-wavelength mode in the MIR and THz regions via surface phonon polariton (SPhP)mode' stimulation within the Reststrahlen band, a narrow spectral range between transverse optical (TO) and longitudinal optical (LO) frequencies. Due to the excellent polaritonic responses in both graphene and silicon carbide in the MIR and THz regions, devices c...
Within the past decades, flooding has become a global pandemic, which hampers economic and social... more Within the past decades, flooding has become a global pandemic, which hampers economic and social development. This global phenomenon has led to loss of lives and economic damages in many countries including Ghana. On June 3rd 2015, Accra, Ghana's capital experienced an unprecedented flash flood event, coupled with an explosion at a Goil filling station that resulted in a death toll of over 152 lives. It is therefore necessary to explore new ideas and approaches that can be incorporated to existing structures to manage this problem. The aim of this study is to analyse the underlying causes of flood in Accra, examine the suitable structural measures that can be undertaken to mitigate flood impacts in Accra, and propose a mitigation approach to manage flood impacts using Integrated Flood Risk Management and Sustainable Flood Management. The Intensity of rainfall events in eight drainage basins in Accra namely; Kpeshie, Korle, Densu, Sakumo, Lafa, Osu, Songo Mokwe and Chemu trigger...
Nanomaterials, 2021
The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational... more The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational fingerprints. There is a growing interest in nanophotonics operating in this spectral range, and recent advances in plasmonic research are aimed at enhancing MIR infrared nanophotonics. In particular, the design of hybrid plasmonic metasurfaces has emerged as a promising route to realize novel MIR applications. Here we demonstrate a hybrid nanostructure combining graphene and silicon carbide to extend the spectral phonon response of silicon carbide and enable absorption and field enhancement of the MIR photon via the excitation and hybridization of surface plasmon polaritons and surface phonon polaritons. We combine experimental methods and finite element simulations to demonstrate enhanced absorption of MIR photons and the broadening of the spectral resonance of graphene-coated silicon carbide nanowires. We also indicate subwavelength confinement of the MIR photons within a thin oxide ...
Journal of Physics: Materials, 2020
The ability to control the interaction of light and matter at the nanoscale is at the heart of th... more The ability to control the interaction of light and matter at the nanoscale is at the heart of the field of nanophotonics. This subdiffractional confinement of light can be achieved through the stimulation of surface polaritons, most notably surface plasmon polaritons (SPPs). However, the high optical losses and lack of tunability of conventional plasmonic materials have hindered major progress in this field. In the search for alternative low-loss and tunable materials, graphene and polar dielectric materials are viewed as potential alternatives to more common metal-based plasmonic materials. In particular, the possibility of combining the tunable nature of graphene SPPs with the high-quality factors and long lifetimes of surface phonon-polaritons (SPhPs) modes supported in polar dielectric materials (e.g. SiC) offers great promise for advanced nanophotonic applications. The combination of graphene SPPs and SPhPs supported in SiC is even more pertinent as this material system can be...
Journal of Nanophotonics, 2018
The current state of energy is characterized by complex challenges in production processes and en... more The current state of energy is characterized by complex challenges in production processes and environmental issues. With the world population continuing to multiply faster and the globalization process, additional energy production is needed to meet future demands. Solar energy is one of the best sustainable energy resources, which is expected to play a vital role in this scenario. One of the best techniques to harvest this resource is through solar photovoltaic technology, which produces electricity directly from solar radiation. But, one of the problems still persisting is its low efficiency. To harness this technology, this problem needs to be addressed. Metamaterial (MTM) technology has enabled the creation of advanced devices for various applications. Solar cell technology is one of the fields to benefit from this technology. MTM perfect absorber can be used in solar cells to improve their absorption. Multiple-bands MTM absorber for next generation high-efficiency solar cells is proposed. The design gives a nearly perfect absorption (99.94%) with a bandwidth of 23.4% in visible spectrum. In addition, the geometric flexibility of a proposed design causes its absorption rate to be insensitive of polarization angles and angles of incident electromagnetic radiations.
Applied Physics A, 2016
This paper suggests a metamaterial (MTM) absorber structure to be used for efficiency improved so... more This paper suggests a metamaterial (MTM) absorber structure to be used for efficiency improved solar cell. The proposed MTM absorber consists of the topmost three concentric circular ring resonators, and a ground metal plane sandwiched to the top layer with a dielectric spacer. Numerical simulation and theoretical (interference theory) studies on the proposed design show a wideband with near-perfect (>99%) absorption response in the visible frequency region of the solar spectrum. Thermal characterization of the suggested design is also conducted in order to investigate its absorption capability at different temperatures. The proposed MTM absorber design is believed to be an outstanding candidate toward high-efficiency solar photovoltaic cell.
Journal of Alloys and Compounds, 2016
Since the discovery of metamaterial absorber to the present days, several designs were proposed w... more Since the discovery of metamaterial absorber to the present days, several designs were proposed which display single-, dual-, and multiple-bands absorption responses in almost all regions of solar spectrum. However, little work has been done for wide-band metamaterial absorber in the visible frequency range. Hence, a novel wide-band metamaterial perfect absorber (MPA) based on concentric Circular Ring Resonator (CRR) topology is proposed for the application to improve the absorbance of solar photovoltaic cells for the visible frequency region. The proposed design consists of three basic components as resonators, ground metal, and dielectric spacer. The geometrical parametric study is conducted in order to investigate the flexibility of the proposed MPA structure. The design flexibility also analyzed by the polarization angle insensitivity character, in which the proposed design provides the perfect absorption for different angles of the incident electromagnetic wave as well as for TE and TM polarized waves.
Journal of Alloys and Compounds, 2016
This paper proposes a metamaterial absorber design for solar energy harvesting using a simplified... more This paper proposes a metamaterial absorber design for solar energy harvesting using a simplified and symmetric structure. A unit cell of this design consists of three important layers namely, the bottom metallic layer, which is gold lossy, the intermediate layer: made of a lossy dielectric material that is gallium arsenide and patches which formed by a combination of gold and gallium arsenide. These three important layers are being carefully arranged at the top of a dielectric spacer. The geometric structure was being examined for its contribution towards absorption characteristics. The simulation results show outstanding dual-bands absorption (99.96% and 99.37%) in the visible frequency regime of electromagnetic wave. Due to the excellent symmetric nature of the proposed structure, its absorptance capacity exhibits polarization insensitivity for a wide range of incident angles for electromagnetic radiation.
physica status solidi (c), 2015
A metamaterial absorber that effectively harvests solar energy is being proposed in this paper us... more A metamaterial absorber that effectively harvests solar energy is being proposed in this paper using a simple and high flexible structure. The proposed structure unit cell comprises of three vital layers. The ground metallic plane, an intermediate dielectric spacer while patches are wisely prepared on the top of a dielectric spacer. Geometrical parameters of the proposed metamaterial is studied in order to get insight on their impact for the absorption behaviour of the structure. The results from simulation provides two excellent absorption resonance (99.96% and 99.37%) in the visible spectrum range of electromagnetic wave. Due to the excellent symmetry of the proposed metamaterial design, its absorption coefficient is polarisation insensitive for a wide range of incident angles of electromagnetic radiations.
IET Optoelectronics, 2016
Developing a perfect absorber based on metamaterials (MTMs) is a promising technique towards impr... more Developing a perfect absorber based on metamaterials (MTMs) is a promising technique towards improving the efficiency of solar photovoltaic cells. In this study, a novel MTM-based perfect absorber (MPA) is proposed for solar cell applications, which exhibits an excellent single-band with high absorption rate of 99.7% in visible frequency regime (resonance frequency of 614.4 THz) with an outstanding absorption bandwidth of 15.5%. The proposed design presents a high symmetry flexibility which makes it easy to fabricate. Besides, the simulation results for the defined different incident angles and different polarisation (transverse electric and transverse magnetic) confirm the quality of the proposed design by showing how insensitive it is to both the defined incident angles (normal and oblique incident) and different polarisation angles of electromagnetic wave. The parametric study on dielectric spacer shows the tunability characteristic of an intended MPA structure. The proposed MPA design is a good candidate for fabrication of high-efficiency solar cell operating in a visible frequency range.
The mid-infrared optical spectrum hosts a variety of promising photonic applications. Herein we s... more The mid-infrared optical spectrum hosts a variety of promising photonic applications. Herein we simulate and experimentally demonstrate reflectance enhancement of MIR light using graphene-coated silicon carbide nanowires on silicon, showing promise for on-chip MIR Nano photonics.
Nanomaterials
The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational... more The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational fingerprints. There is a growing interest in nanophotonics operating in this spectral range, and recent advances in plasmonic research are aimed at enhancing MIR infrared nanophotonics. In particular, the design of hybrid plasmonic metasurfaces has emerged as a promising route to realize novel MIR applications. Here we demonstrate a hybrid nanostructure combining graphene and silicon carbide to extend the spectral phonon response of silicon carbide and enable absorption and field enhancement of the MIR photon via the excitation and hybridization of surface plasmon polaritons and surface phonon polaritons. We combine experimental methods and finite element simulations to demonstrate enhanced absorption of MIR photons and the broadening of the spectral resonance of graphene-coated silicon carbide nanowires. We also indicate subwavelength confinement of the MIR photons within a thin oxide ...
Enhanced Absorption with Graphene-Coated Silicon Carbide Nanowires for Mid-Infrared Nanophotonics, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
ABSTRACT The efficiency of photovoltaic cells (PV) has been one of the major problem impeding its... more ABSTRACT The efficiency of photovoltaic cells (PV) has been one of the major problem impeding its global adoption as a sustainable substitute to fossil fuel based technologies. Metamaterials (MTM) based solar cells offers a unique opportunity towards increasing the system efficiency by enhancing the total absorbed solar radiation incident on this device. In this study, a nanostructure based MTM perfect absorber has been designed and simulated. By adjusting geometrical parameters and MTM properties of the structure, nearly perfect dual-band resonances were obtained. The two bands peaked at 524.5 THz and 655 THz with corresponding absorption of 99.99 % and 99.8 %, respectively. The proposed structure is simple and more flexible for adjustment, which help to achievement of multiple and wide bands. Implementation of the designed structure can effectively lead to the realization of more efficiency PV solar cells.
Journal of Nanophotonics
A wideband metamaterial (MTM) absorber based on a concentric ring resonator is discussed at visib... more A wideband metamaterial (MTM) absorber based on a concentric ring resonator is discussed at visible frequencies. The proposed structure offers a wideband absorption response, where absorption of >70% is gained for the frequency ranging from 537.91 to 635.73 THz. The analysis is conducted on the components of the proposed structure to understand the origin of wideband absorption. Furthermore, a graphene monolayer sheet is integrated to the proposed MTM absorber to optimize its absorptivity, where the studies show enhancement of the absorptivity of the proposed structure up to 26% from its initial absorptivity. MTM absorbers of this kind have potential applications in solar cells.
Journal of Physics: Materials, 2020
The ability to control the interaction of light and matter at the nanoscale is at the heart of th... more The ability to control the interaction of light and matter at the nanoscale is at the heart of the field of nanophotonics. This subdiffractional confinement of light can be achieved through the stimulation of surface polaritons, most notably surface plasmon polaritons (SPPs). However, the high optical losses and lack of tunability of conventional plasmonic materials have hindered major progress in this field. In the search for alternative low-loss and tunable materials, graphene and polar dielectric materials are viewed as potential alternatives to more common metal-based plasmonic materials. In particular, the possibility of combining the tunable nature of graphene SPPs with the high-quality factors and long lifetimes of surface phonon-polaritons (SPhPs) modes supported in polar dielectric materials (e.g., SiC) offers great promise for advanced nanophotonic applications. The combination of graphene SPPs and SPhPs supported in SiC is even more pertinent as this material system can be realized in the form of epitaxial graphene (EG), whereby sublimation of silicon from a SiC results in a surface reconstruction into a graphene surface termination. This offers an ideal technology platform for realizing hybrid SPP-SPhP modes. In this review, we outline advances in graphene plasmonics and the generation of SPhPs in polar materials, in the context of epitaxial graphene. We review recent attempts at realizing such coupling of graphene SPPs with phonon and SPhP modes in SiC, as well as covering such modes in other polar materials and conclude with an overview of advantages and challenges for further advancement of nanophotonics based on graphene on silicon carbide for on-chip light manipulation.
Patrick Rufangura, Cumali Sabah, "Perfect metamaterial absorber for applications in sustainable a... more Patrick Rufangura, Cumali Sabah, "Perfect metamaterial absorber for applications in sustainable and highefficiency solar cells,"