The Experts below are selected from a list of 2052 Experts worldwide ranked by ideXlab platform
Mathias Schubert - One of the best experts on this subject based on the ideXlab platform.
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Electromagnon excitation in Cupric Oxide measured by Fabry-Pérot enhanced terahertz Mueller matrix ellipsometry
Scientific Reports, 2019Co-Authors: Sean Knight, Christian Binek, Dharmalingam Prabhakaran, Mathias SchubertAbstract:Here we present the use of Fabry-Pérot enhanced terahertz (THz) Mueller matrix ellipsometry to measure an electromagnon excitation in monoclinic Cupric Oxide (CuO). As a magnetically induced ferroelectric multiferroic, CuO exhibits coupling between electric and magnetic order. This gives rise to special quasiparticle excitations at THz frequencies called electromagnons. In order to measure the electromagnons in CuO, we exploit single-crystal CuO as a THz Fabry-Pérot cavity to resonantly enhance the excitation’s signature. This enhancement technique enables the complex index of refraction to be extracted. We observe a peak in the absorption coefficient near 0.705 THz and 215 K, which corresponds to the electromagnon excitation. This absorption peak is observed along only one major polarizability axis in the monoclinic a–c plane. We show the excitation can be represented using the Lorentz oscillator model, and discuss how these Lorentz parameters evolve with temperature. Our findings are in excellent agreement with previous characterizations by THz time-domain spectroscopy (THz-TDS), which demonstrates the validity of this enhancement technique.
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electromagnon excitation in Cupric Oxide measured by fabry perot enhanced terahertz mueller matrix ellipsometry
Scientific Reports, 2019Co-Authors: Sean Knight, Christian Binek, Dharmalingam Prabhakaran, Mathias SchubertAbstract:Here we present the use of Fabry-Perot enhanced terahertz (THz) Mueller matrix ellipsometry to measure an electromagnon excitation in monoclinic Cupric Oxide (CuO). As a magnetically induced ferroelectric multiferroic, CuO exhibits coupling between electric and magnetic order. This gives rise to special quasiparticle excitations at THz frequencies called electromagnons. In order to measure the electromagnons in CuO, we exploit single-crystal CuO as a THz Fabry-Perot cavity to resonantly enhance the excitation’s signature. This enhancement technique enables the complex index of refraction to be extracted. We observe a peak in the absorption coefficient near 0.705 THz and 215 K, which corresponds to the electromagnon excitation. This absorption peak is observed along only one major polarizability axis in the monoclinic a–c plane. We show the excitation can be represented using the Lorentz oscillator model, and discuss how these Lorentz parameters evolve with temperature. Our findings are in excellent agreement with previous characterizations by THz time-domain spectroscopy (THz-TDS), which demonstrates the validity of this enhancement technique.
Sean Knight - One of the best experts on this subject based on the ideXlab platform.
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Electromagnon excitation in Cupric Oxide measured by Fabry-Pérot enhanced terahertz Mueller matrix ellipsometry
Scientific Reports, 2019Co-Authors: Sean Knight, Christian Binek, Dharmalingam Prabhakaran, Mathias SchubertAbstract:Here we present the use of Fabry-Pérot enhanced terahertz (THz) Mueller matrix ellipsometry to measure an electromagnon excitation in monoclinic Cupric Oxide (CuO). As a magnetically induced ferroelectric multiferroic, CuO exhibits coupling between electric and magnetic order. This gives rise to special quasiparticle excitations at THz frequencies called electromagnons. In order to measure the electromagnons in CuO, we exploit single-crystal CuO as a THz Fabry-Pérot cavity to resonantly enhance the excitation’s signature. This enhancement technique enables the complex index of refraction to be extracted. We observe a peak in the absorption coefficient near 0.705 THz and 215 K, which corresponds to the electromagnon excitation. This absorption peak is observed along only one major polarizability axis in the monoclinic a–c plane. We show the excitation can be represented using the Lorentz oscillator model, and discuss how these Lorentz parameters evolve with temperature. Our findings are in excellent agreement with previous characterizations by THz time-domain spectroscopy (THz-TDS), which demonstrates the validity of this enhancement technique.
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electromagnon excitation in Cupric Oxide measured by fabry perot enhanced terahertz mueller matrix ellipsometry
Scientific Reports, 2019Co-Authors: Sean Knight, Christian Binek, Dharmalingam Prabhakaran, Mathias SchubertAbstract:Here we present the use of Fabry-Perot enhanced terahertz (THz) Mueller matrix ellipsometry to measure an electromagnon excitation in monoclinic Cupric Oxide (CuO). As a magnetically induced ferroelectric multiferroic, CuO exhibits coupling between electric and magnetic order. This gives rise to special quasiparticle excitations at THz frequencies called electromagnons. In order to measure the electromagnons in CuO, we exploit single-crystal CuO as a THz Fabry-Perot cavity to resonantly enhance the excitation’s signature. This enhancement technique enables the complex index of refraction to be extracted. We observe a peak in the absorption coefficient near 0.705 THz and 215 K, which corresponds to the electromagnon excitation. This absorption peak is observed along only one major polarizability axis in the monoclinic a–c plane. We show the excitation can be represented using the Lorentz oscillator model, and discuss how these Lorentz parameters evolve with temperature. Our findings are in excellent agreement with previous characterizations by THz time-domain spectroscopy (THz-TDS), which demonstrates the validity of this enhancement technique.
Dharmalingam Prabhakaran - One of the best experts on this subject based on the ideXlab platform.
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Electromagnon excitation in Cupric Oxide measured by Fabry-Pérot enhanced terahertz Mueller matrix ellipsometry
Scientific Reports, 2019Co-Authors: Sean Knight, Christian Binek, Dharmalingam Prabhakaran, Mathias SchubertAbstract:Here we present the use of Fabry-Pérot enhanced terahertz (THz) Mueller matrix ellipsometry to measure an electromagnon excitation in monoclinic Cupric Oxide (CuO). As a magnetically induced ferroelectric multiferroic, CuO exhibits coupling between electric and magnetic order. This gives rise to special quasiparticle excitations at THz frequencies called electromagnons. In order to measure the electromagnons in CuO, we exploit single-crystal CuO as a THz Fabry-Pérot cavity to resonantly enhance the excitation’s signature. This enhancement technique enables the complex index of refraction to be extracted. We observe a peak in the absorption coefficient near 0.705 THz and 215 K, which corresponds to the electromagnon excitation. This absorption peak is observed along only one major polarizability axis in the monoclinic a–c plane. We show the excitation can be represented using the Lorentz oscillator model, and discuss how these Lorentz parameters evolve with temperature. Our findings are in excellent agreement with previous characterizations by THz time-domain spectroscopy (THz-TDS), which demonstrates the validity of this enhancement technique.
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electromagnon excitation in Cupric Oxide measured by fabry perot enhanced terahertz mueller matrix ellipsometry
Scientific Reports, 2019Co-Authors: Sean Knight, Christian Binek, Dharmalingam Prabhakaran, Mathias SchubertAbstract:Here we present the use of Fabry-Perot enhanced terahertz (THz) Mueller matrix ellipsometry to measure an electromagnon excitation in monoclinic Cupric Oxide (CuO). As a magnetically induced ferroelectric multiferroic, CuO exhibits coupling between electric and magnetic order. This gives rise to special quasiparticle excitations at THz frequencies called electromagnons. In order to measure the electromagnons in CuO, we exploit single-crystal CuO as a THz Fabry-Perot cavity to resonantly enhance the excitation’s signature. This enhancement technique enables the complex index of refraction to be extracted. We observe a peak in the absorption coefficient near 0.705 THz and 215 K, which corresponds to the electromagnon excitation. This absorption peak is observed along only one major polarizability axis in the monoclinic a–c plane. We show the excitation can be represented using the Lorentz oscillator model, and discuss how these Lorentz parameters evolve with temperature. Our findings are in excellent agreement with previous characterizations by THz time-domain spectroscopy (THz-TDS), which demonstrates the validity of this enhancement technique.
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high temperature electromagnons in the magnetically induced multiferroic Cupric Oxide driven by intersublattice exchange
Nature Communications, 2014Co-Authors: S P P Jones, Dharmalingam Prabhakaran, S M Gaw, K I Doig, E Hetroy M Wheeler, A T Boothroyd, J LloydhughesAbstract:Magnetically induced ferroelectric multiferroics present an exciting new paradigm in the design of multifunctional materials, by intimately coupling magnetic and polar order. Magnetoelectricity creates a novel quasiparticle excitation--the electromagnon--at terahertz frequencies, with spectral signatures that unveil important spin interactions. To date, electromagnons have been discovered at low temperature (<70 K) and predominantly in rare-earth compounds such as RMnO3. Here we demonstrate using terahertz time-domain spectroscopy that intersublattice exchange in the improper multiferroic Cupric Oxide (CuO) creates electromagnons at substantially elevated temperatures (213-230 K). Dynamic magnetoelectric coupling can therefore be achieved in materials, such as CuO, that exhibit minimal static cross-coupling. The electromagnon strength and energy track the static polarization, highlighting the importance of the underlying cycloidal spin structure. Polarized neutron scattering and terahertz spectroscopy identify a magnon in the antiferromagnetic ground state, with a temperature dependence that suggests a significant role for biquadratic exchange.
Saeid Masudypanah - One of the best experts on this subject based on the ideXlab platform.
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nanoengineered advanced materials for enabling hydrogen economy functionalized graphene incorporated Cupric Oxide catalyst for efficient solar hydrogen production
Global challenges (Hoboken NJ), 2020Co-Authors: G K Dalapati, Saeid Masudypanah, Roozbeh Siavash Moakhar, Sabyasachi Chakrabortty, Siddhartha Ghosh, Ajay Kushwaha, Reza Katal, Chin Sheng Chua, Gong XiaoAbstract:: Cupric Oxide (CuO) is a promising candidate as a photocathode for visible-light-driven photo-electrochemical (PEC) water splitting. However, the stability of the CuO photocathode against photo-corrosion is crucial for developing CuO-based PEC cells. This study demonstrates a stable and efficient photocathode through the introduction of graphene into CuO film (CuO:G). The CuO:G composite electrodes are prepared using graphene-incorporated CuO sol-gel solution via spin-coating techniques. The graphene is modified with two different types of functional groups, such as amine (-NH2) and carboxylic acid (-COOH). The -COOH-functionalized graphene incorporation into CuO photocathode exhibits better stability and also improves the photocurrent generation compare to control CuO electrode. In addition, -COOH-functionalized graphene reduces the conversion of CuO phase into cuprous Oxide (Cu2O) during photo-electrochemical reaction due to effective charge transfer and leads to a more stable photocathode. The reduction of CuO to Cu2O phase is significantly lesser in CuO:G-COOH as compared to CuO and CuO:G-NH2 photocathodes. The photocatalytic degradation of methylene blue (MB) by CuO, CuO:G-NH2 and CuO:G-COOH is also investigated. By integrating CuO:G-COOH photocathode with a sol-gel-deposited TiO2 protecting layer and Au-Pd nanostructure, stable and efficient photocathode are developed for solar hydrogen generation.
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a high performance Cupric Oxide photocatalyst with palladium light trapping nanostructures and a hole transporting layer for photoelectrochemical hydrogen evolution
Journal of Materials Chemistry, 2019Co-Authors: Saeid Masudypanah, Reza Katal, Negar Dasineh Khiavi, Ehsan Shekarian, Xiao GongAbstract:The high recombination rate of photogenerated electron–hole pairs, poor photocorrosion stability, and the discrepancy between the optical absorption length and charge collection efficiency of Cupric Oxide (CuO) are the main limiting factors of visible-light-driven CuO photocatalysts for hydrogen evolution and photocatalytic degradation of organic pollutants. In this paper, we demonstrate a novel thin CuO film photocatalyst on a fluorine doped tin Oxide (FTO) coated glass substrate with low back contact resistivity, high charge collection efficiency, high optical absorption, and high photocorrosion stability for hydrogen production and photocatalytic degradation of organic pollutants. This photocatalyst was fabricated by incorporating palladium (Pd) nanostructures into CuO to form a CuO:Pd light trapping thin film. The CuO:Pd light trapping thin film was then sandwiched between a nitrogen doped Cupric Oxide [CuO(N)] hole transporting layer and a CuO capping layer [CuO(N)–CuO:Pd–CuO]. The performance of the CuO(N)–CuO:Pd–CuO photocatalyst is further improved by incorporating a ZnO buffer layer and TiO2 protective layer, and decorating with a AuPd co-catalyst. Moreover, we demonstrate a significant improvement of photocorrosion stability and photocatalytic degradation efficiency of the CuO(N)–CuO:Pd–CuO–ZnO–TiO2 photocatalyst through plasma assisted in situ nano-crystal engineering of the ZnO buffer layer and TiO2 protective layer. The fabricated novel photocatalyst could retain 95% of the initial photocurrent density after 6 hours of standard illumination with solar light and could give a record high photocurrent density of ∼8 mA cm−2 for the CuO photocatalyst.
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palladium nanostructure incorporated Cupric Oxide thin film with strong optical absorption compatible charge collection and low recombination loss for low cost solar cell applications
Nano Energy, 2018Co-Authors: Hui Ru Tan, Saeid Masudypanah, Xiao Gong, Siarhei Zhuk, G K DalapatiAbstract:Abstract Cupric Oxide (CuO) is one of the most promising and low-cost materials for solar cell application, but its power conversion efficiency is limited by discrepancy between short carrier diffusion length and optical absorption length, low charge collection efficiency, and high recombination rate. We present a novel optical absorbing CuO film to simultaneously address all of these issues by combining thin films of palladium (Pd) nanoparticles-incorporated CuO (CuO:Pd), nitrogen-doped CuO (CuO:N), and nitrogen-doped cuprous Oxide (Cu2O:N). Incorporation of Pd nanoparticles significantly increases photo-generated charge collection efficiency and enhances optical absorption over the wide range of solar spectrum. Graded refractive index and step distribution of carrier concentration of Cu2O:N/CuO:N thin films reduce optical reflectance and build high potential into optical absorbing thin film. The Cu2O:N/CuO:N/CuO:Pd/CuO thin film increases charge collection efficiency and reduces recombination rates. Using this design, record high short circuit current density (Jsc) and efficiency (η) of around 28.5 mA cm−2 and 8.3 are achieved, respectively, for heterojunction solar cell using Cu2O:N/CuO:N/CuO:Pd/CuO thin film on titanium (Ti) passivated n-type silicon (Si) substrate (p-(Cu2O:N/CuO:N/CuO:Pd/CuO)/Ti/n-Si). Jsc and η for p-(Cu2O:N/CuO:N/CuO:Pd/CuO)/Ti/n-Si solar cell are around 14 and 40 times higher than the control p-CuO/n-Si solar cell, respectively. This work provides a novel approach to achieve high efficiency CuO-based thin film solar cells.
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titanium doped Cupric Oxide for photovoltaic application
Solar Energy Materials and Solar Cells, 2015Co-Authors: K Radhakrishnan, Saeid Masudypanah, Hui Ru Tan, Ten It Wong, G K DalapatiAbstract:Abstract The potential of titanium (Ti) incorporation into Cupric Oxide (CuO) is demonstrated. The optical, electrical, microstructural, material quality, chemical composition, surface morphology, and photovoltaic properties of Ti doped CuO, CuO(Ti) have been systematically investigated. It is shown that Ti doped CuO reduces sheet resistance and improved the charge transport properties. Furthermore, by tuning the Ti concentration, the conductivity of CuO(Ti) can be improved, while retaining the optical properties and crystallinity of the samples. Heterojunction solar cells of p -type Ti doped CuO on n -type silicon (Si) substrate, p -CuO(Ti)/ n -Si, prepared by using conventional sputter deposition at room temperature followed by rapid thermal annealing at 300 °C to investigate the impact of Ti doped CuO on the performance of photovoltaic properties. The short circuit current and efficiency of p -CuO(Ti)/ n -Si heterojunction have been significantly improved compared to the cells without Ti doped CuO.
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defect analysis of sputter grown Cupric Oxide for optical and electronics application
Science & Engineering Faculty, 2015Co-Authors: G K Dalapati, Saeid Masudypanah, R S Kajen, Prashant SonarAbstract:We have studied the defect density and defect level of sputter grown Cupric Oxide (CuO) for optical and electronic applications. A deep level transient spectroscopy (DLTS) technique has been employed to study the defect density in the CuO thin film deposited by sputtering. The DLTS studied showed that the defect density significantly reduced for the film grown at a high working pressure. It has also been shown that doping density increases for the film grown at a high working pressure. Transmission electron microscopy analysis revealed the improvement of the crystal quality of the CuO thin film prepared at the high working pressure. The band gap of sputter grown CuO was found to be ~1.4 eV with an absorption coefficient of ~104 cm−1. From a photoelectron spectroscopy measurement, it was found that the work function for CuO was ~5.2 eV. The present work reveals the importance of CuO for optical and electronic device applications.
Christian Binek - One of the best experts on this subject based on the ideXlab platform.
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Electromagnon excitation in Cupric Oxide measured by Fabry-Pérot enhanced terahertz Mueller matrix ellipsometry
Scientific Reports, 2019Co-Authors: Sean Knight, Christian Binek, Dharmalingam Prabhakaran, Mathias SchubertAbstract:Here we present the use of Fabry-Pérot enhanced terahertz (THz) Mueller matrix ellipsometry to measure an electromagnon excitation in monoclinic Cupric Oxide (CuO). As a magnetically induced ferroelectric multiferroic, CuO exhibits coupling between electric and magnetic order. This gives rise to special quasiparticle excitations at THz frequencies called electromagnons. In order to measure the electromagnons in CuO, we exploit single-crystal CuO as a THz Fabry-Pérot cavity to resonantly enhance the excitation’s signature. This enhancement technique enables the complex index of refraction to be extracted. We observe a peak in the absorption coefficient near 0.705 THz and 215 K, which corresponds to the electromagnon excitation. This absorption peak is observed along only one major polarizability axis in the monoclinic a–c plane. We show the excitation can be represented using the Lorentz oscillator model, and discuss how these Lorentz parameters evolve with temperature. Our findings are in excellent agreement with previous characterizations by THz time-domain spectroscopy (THz-TDS), which demonstrates the validity of this enhancement technique.
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electromagnon excitation in Cupric Oxide measured by fabry perot enhanced terahertz mueller matrix ellipsometry
Scientific Reports, 2019Co-Authors: Sean Knight, Christian Binek, Dharmalingam Prabhakaran, Mathias SchubertAbstract:Here we present the use of Fabry-Perot enhanced terahertz (THz) Mueller matrix ellipsometry to measure an electromagnon excitation in monoclinic Cupric Oxide (CuO). As a magnetically induced ferroelectric multiferroic, CuO exhibits coupling between electric and magnetic order. This gives rise to special quasiparticle excitations at THz frequencies called electromagnons. In order to measure the electromagnons in CuO, we exploit single-crystal CuO as a THz Fabry-Perot cavity to resonantly enhance the excitation’s signature. This enhancement technique enables the complex index of refraction to be extracted. We observe a peak in the absorption coefficient near 0.705 THz and 215 K, which corresponds to the electromagnon excitation. This absorption peak is observed along only one major polarizability axis in the monoclinic a–c plane. We show the excitation can be represented using the Lorentz oscillator model, and discuss how these Lorentz parameters evolve with temperature. Our findings are in excellent agreement with previous characterizations by THz time-domain spectroscopy (THz-TDS), which demonstrates the validity of this enhancement technique.
