This work presents an investigation of nanoribbons cut from β_(12)-borophene sheets by applying the density functional theory. In particular, the electronic and magnetic properties of borophene nanoribbons(BNR) are s...This work presents an investigation of nanoribbons cut from β_(12)-borophene sheets by applying the density functional theory. In particular, the electronic and magnetic properties of borophene nanoribbons(BNR) are studied. It is found that all the ribbons considered in this work behave as metals, which is in good agreement with the recent experimental results. β_(12)-BNR has significant diversity due to the existence of five boron atoms in a unit cell of the sheet. The magnetic properties of the ribbons are strongly dependent on the cutting direction and edge profile. It is interesting that a ribbon with a specific width can behave as a normal or a ferromagnetic metal with magnetization at just one edge or two edges. Spin anisotropy is observed in some ribbons, and the magnetic moment is not found to be the same in both edges in an antiferromagnetic configuration. This effect stems from the edge asymmetry of the ribbons and results in the breaking of spin degeneracy in the band structure. Our findings show that β_(12) BNRs are potential candidates for next-generation spintronic devices.展开更多
In this paper, a novel method of producing nanoparticles at low temperatures using hydrogen bombardment of thin films, deposited on glass substrates, is introduced. Silver nanoparticles were obtained by this method in...In this paper, a novel method of producing nanoparticles at low temperatures using hydrogen bombardment of thin films, deposited on glass substrates, is introduced. Silver nanoparticles were obtained by this method in our Plasma Enhanced Chemical Vapor Deposition system. Optical and morphological characteristics of these nanoparticles were extensively studied for various conditions of plasma treatment, such as plasma power density, temperature, duration of hydrogen bombardment, thickness of the initial thin metallic film etc. In addition, Ag-Cu alloy nanoparticles on glass substrates were also achieved. The process of nanoparticle formation in this method shows that several kinds of metals and semiconductors nanoparticles can be obtained using this approach. Scanning Electron Microscopy, Atomic Force Microscopy and Transmission Electron Microscopy were used to analyze the nanostructures.展开更多
The slow light propagation in a line defect waveguide in chalcogenide photonic crystal of As2S3 rods in air medium has been investigated. It is found that the filling factor of the chaleogenide photonic crystal and th...The slow light propagation in a line defect waveguide in chalcogenide photonic crystal of As2S3 rods in air medium has been investigated. It is found that the filling factor of the chaleogenide photonic crystal and the size of defect rods decide the propagation of the guided mode. An increase in the filling factor results in a sharp decrease of the group velocity in the photonic crystal waveguide. It has been demonstrated that, by tuning the filling factor and size of defect rods, the group velocity will be reduced up to about 0.22c.展开更多
In this study, the thermoelectric properties of pyrene molecule doped with boron and nitrogen atom at different sites of molecule are investigated using density functional theory and none-equilibrium Greens function f...In this study, the thermoelectric properties of pyrene molecule doped with boron and nitrogen atom at different sites of molecule are investigated using density functional theory and none-equilibrium Greens function formalism in the linear response regime. Our calculations show that when the impurities are added to the edge of the molecule, the anti-resonant peaks will appear in the transmission diagram in the vicinity of the Fermi energy level. So it increases the thermoelectric figure of merit of the system in comparison with the one that the impurity is located in the center of molecule. Additionally, the seebeck coefficient signs are not the same among the B, N, and N ＆ B doped devices, indicating that the types of the carriers can be changed with different types of doping.展开更多
Thermal and electron transport through organic molecules attached to three-dimensional gold electrodes in two different configurations, namely para and meta with thiol-terminated junctions is studied theoretically in ...Thermal and electron transport through organic molecules attached to three-dimensional gold electrodes in two different configurations, namely para and meta with thiol-terminated junctions is studied theoretically in the linear response regime using Green＇s function formalism. We used thiol-terminated（–SH bond） benzene units and found a positive thermopower because the highest occupied molecular orbital（HOMO） is near the Fermi energy level. We investigated the influence of molecular length and molecular junction geometry on the thermoelectric properties. Our results show that the thermoelectric properties are highly sensitive to the coupling geometry and the molecular length. In addition, we observed that the interference effects and increasing molecular length can increase the thermoelectric efficiency of device in a specific configuration.展开更多
Plasma treatment constitutes an efficient method for chemical-free disinfection.A spray-based system for dispensing plasma-activated aerosols onto surfaces would facilitate disinfection of complex and/or hidden surfac...Plasma treatment constitutes an efficient method for chemical-free disinfection.A spray-based system for dispensing plasma-activated aerosols onto surfaces would facilitate disinfection of complex and/or hidden surfaces inaccessible to direct line-of-sight(for example,UV)methods.The complexity and size of current plasma generators(for example,plasma jet and cometary plasma systems)-which prohibit portable operation,together with the short plasma lifetimes,necessitate a miniaturized in situ technique in which a source can be simultaneously activated and administered on-demand onto surfaces.Here,we demonstrate this possibility by combining two nanoscale technologies for plasma and aerosol generation into an integrated device that is sufficiently small and lightweight.Plasma is generated on a carpet of zinc oxide nanorods comprising a nanoneedle ensemble,which when raised to a high electric potential,constitutes a massive point charge array with near-singular electric fields to effect atmospheric breakdown.The plasma is then used to activate water transported through an underlying capillary wick,that is subsequently aerosolized under MHz-order surface acoustic waves.We show that the system,besides being amenable to miniaturization and hence integration into a chipscale device,leads to a considerable improvement in plasma-activation over its macroscale cometary discharge predecessor,with up to 20%and 127%higher hydrogen peroxide and nitrite ion concentrations that are respectively generated in the plasma-activated aerosols.This,in turn,leads to a 67%reduction in the disinfection time to achieve 95%bacterial load reduction,therefore demonstrating the potential of the technology as an efficient portable platform for on-demand field-use surface disinfection.展开更多
文摘This work presents an investigation of nanoribbons cut from β_(12)-borophene sheets by applying the density functional theory. In particular, the electronic and magnetic properties of borophene nanoribbons(BNR) are studied. It is found that all the ribbons considered in this work behave as metals, which is in good agreement with the recent experimental results. β_(12)-BNR has significant diversity due to the existence of five boron atoms in a unit cell of the sheet. The magnetic properties of the ribbons are strongly dependent on the cutting direction and edge profile. It is interesting that a ribbon with a specific width can behave as a normal or a ferromagnetic metal with magnetization at just one edge or two edges. Spin anisotropy is observed in some ribbons, and the magnetic moment is not found to be the same in both edges in an antiferromagnetic configuration. This effect stems from the edge asymmetry of the ribbons and results in the breaking of spin degeneracy in the band structure. Our findings show that β_(12) BNRs are potential candidates for next-generation spintronic devices.
文摘In this paper, a novel method of producing nanoparticles at low temperatures using hydrogen bombardment of thin films, deposited on glass substrates, is introduced. Silver nanoparticles were obtained by this method in our Plasma Enhanced Chemical Vapor Deposition system. Optical and morphological characteristics of these nanoparticles were extensively studied for various conditions of plasma treatment, such as plasma power density, temperature, duration of hydrogen bombardment, thickness of the initial thin metallic film etc. In addition, Ag-Cu alloy nanoparticles on glass substrates were also achieved. The process of nanoparticle formation in this method shows that several kinds of metals and semiconductors nanoparticles can be obtained using this approach. Scanning Electron Microscopy, Atomic Force Microscopy and Transmission Electron Microscopy were used to analyze the nanostructures.
基金supported by the CSIR,New Delhi of India under Grant No.08/329/(0008)/2006-EMR-I
文摘The slow light propagation in a line defect waveguide in chalcogenide photonic crystal of As2S3 rods in air medium has been investigated. It is found that the filling factor of the chaleogenide photonic crystal and the size of defect rods decide the propagation of the guided mode. An increase in the filling factor results in a sharp decrease of the group velocity in the photonic crystal waveguide. It has been demonstrated that, by tuning the filling factor and size of defect rods, the group velocity will be reduced up to about 0.22c.
文摘In this study, the thermoelectric properties of pyrene molecule doped with boron and nitrogen atom at different sites of molecule are investigated using density functional theory and none-equilibrium Greens function formalism in the linear response regime. Our calculations show that when the impurities are added to the edge of the molecule, the anti-resonant peaks will appear in the transmission diagram in the vicinity of the Fermi energy level. So it increases the thermoelectric figure of merit of the system in comparison with the one that the impurity is located in the center of molecule. Additionally, the seebeck coefficient signs are not the same among the B, N, and N ＆ B doped devices, indicating that the types of the carriers can be changed with different types of doping.
文摘Thermal and electron transport through organic molecules attached to three-dimensional gold electrodes in two different configurations, namely para and meta with thiol-terminated junctions is studied theoretically in the linear response regime using Green＇s function formalism. We used thiol-terminated（–SH bond） benzene units and found a positive thermopower because the highest occupied molecular orbital（HOMO） is near the Fermi energy level. We investigated the influence of molecular length and molecular junction geometry on the thermoelectric properties. Our results show that the thermoelectric properties are highly sensitive to the coupling geometry and the molecular length. In addition, we observed that the interference effects and increasing molecular length can increase the thermoelectric efficiency of device in a specific configuration.
基金M.K.T.gratefully acknowledges funding for this work from the Fundamental Research Grant Scheme,Ministry of Education,Malaysia,through Project Grant No.FRGS/1/2019/TK03/MUSM/02/1.
文摘Plasma treatment constitutes an efficient method for chemical-free disinfection.A spray-based system for dispensing plasma-activated aerosols onto surfaces would facilitate disinfection of complex and/or hidden surfaces inaccessible to direct line-of-sight(for example,UV)methods.The complexity and size of current plasma generators(for example,plasma jet and cometary plasma systems)-which prohibit portable operation,together with the short plasma lifetimes,necessitate a miniaturized in situ technique in which a source can be simultaneously activated and administered on-demand onto surfaces.Here,we demonstrate this possibility by combining two nanoscale technologies for plasma and aerosol generation into an integrated device that is sufficiently small and lightweight.Plasma is generated on a carpet of zinc oxide nanorods comprising a nanoneedle ensemble,which when raised to a high electric potential,constitutes a massive point charge array with near-singular electric fields to effect atmospheric breakdown.The plasma is then used to activate water transported through an underlying capillary wick,that is subsequently aerosolized under MHz-order surface acoustic waves.We show that the system,besides being amenable to miniaturization and hence integration into a chipscale device,leads to a considerable improvement in plasma-activation over its macroscale cometary discharge predecessor,with up to 20%and 127%higher hydrogen peroxide and nitrite ion concentrations that are respectively generated in the plasma-activated aerosols.This,in turn,leads to a 67%reduction in the disinfection time to achieve 95%bacterial load reduction,therefore demonstrating the potential of the technology as an efficient portable platform for on-demand field-use surface disinfection.
