We analyze the electromagnetic interaction between local surface plasmon polaritons (SPPs) and an atmospheric surface wave plasma jet (ASWPJ) in combination with our designed discharge device. Before discharge, th...We analyze the electromagnetic interaction between local surface plasmon polaritons (SPPs) and an atmospheric surface wave plasma jet (ASWPJ) in combination with our designed discharge device. Before discharge, the excitation of the SPPs and the spatial distribution of the enhanced electric field are analyzed. During discharge, the critical breakdown electric field of the gases at atmospheric gas pressure and the surface wave of the SPPs converted into electron plasma waves at resonant points are studied. After discharge, the ionization development process of the ASWPJ is simulated using a two- dimensional fluid model. Our results suggest that the local enhanced electric field of SPPs is merely the precondition of gas breakdown, and the key mechanism in maintaining the discharge development of a low-power ASWPJ is the wave-mode conversion of the local enhanced electric field at the resonant point.展开更多
A novel plasma limiter, in which the plasma is excited by surface wave, is presented. The breakdown time of some gases filled in the limiter were calculated as a function of gas pres- sure, ionization degree and densi...A novel plasma limiter, in which the plasma is excited by surface wave, is presented. The breakdown time of some gases filled in the limiter were calculated as a function of gas pres- sure, ionization degree and density of seed electrons under low pressure (0.01 -1 Torr) and high pressure (10 -1000 Torr) cases. The results show that the limiter filled with Xe with a pressure of 0.9 Torr, seed electron density of 10^16 m^-3, and ionization degree of 10^-4, has a breakdown time of approximate 19.6 ns.展开更多
Catalyst-free graphene films has been synthesized by microwave (MW) surface wave plasma (SWP) chemical vapor deposition (CVD) using hydrogenated carbon source on silicon substrates at low temperature (500℃). The synt...Catalyst-free graphene films has been synthesized by microwave (MW) surface wave plasma (SWP) chemical vapor deposition (CVD) using hydrogenated carbon source on silicon substrates at low temperature (500℃). The synthesized process is simple, low-cost and possible for application on transparent electrodes, gas sensors and thin film resistors. Analytical methods such as Raman spectroscopy, transmission electron microscopy (TEM) and four points prove resistivity measurement and UV-VIS-NIR spectroscopy were employed to characterize properties of the graphene films. The formation of multilayer of graphene on silicon substrate was confirmed by Raman spectroscopy and TEM. It is possible to grow graphene directly on silicon substrate (without using catalyst) due to high radical density of MW SWP CVD. In addition, we also observed that the hydrogen had significant role for quality of graphene.展开更多
An improved surface wave plasma source equipped with a cylindrical quartz rod has been developed, which has great potential in processing inner wall of cylindrical workpieces. A cylindrical quartz rod not only excites...An improved surface wave plasma source equipped with a cylindrical quartz rod has been developed, which has great potential in processing inner wall of cylindrical workpieces. A cylindrical quartz rod not only excites the plasma around the rod, but also guides surface wave plasma along the rod. The distributions of plasma density and plasma temperature under different incident microwave powers and pressures are diagnosed by a Langmuir probe. The electron density near the rod is around the order of 10^11cm^-3. When the incident power is 450 W, the length of surface wave plasma column can reach up to 420 mm at 20 Pa.展开更多
A novel surface wave plasma (SWP) source excited with cylindrical Teflon waveguide has been developed in our previous work. The plasma characteristics have been simply studied. In this work, our experimental device ...A novel surface wave plasma (SWP) source excited with cylindrical Teflon waveguide has been developed in our previous work. The plasma characteristics have been simply studied. In this work, our experimental device has been significantly improved by replacing the Teflon waveguide with a quartz rod, and then better microwave coupling and higher gas purity can be obtained during plasma discharge. The plasma spatial distributions, both in radial and axial directions, have been measured and the effect of gas pressure has been investigated. Plasma density profiles indicate that this plasma source can produce uniform plasma in an axial direction at low pressure, which shows its potential in plasma processing on a curved surface such as an inner tube wall. A simplified circular waveguide model has been used to explain the principle of plasma excitation. The distinguishing features and potential application of this kind of plasma source with a hardware improvement have been shown.展开更多
The principle of surface wave plasma discharge in a rectangular cavity is introduced simply based on surface plasmon polariton theory. The distribution of surface-wave electric field at the interface of the plasma-die...The principle of surface wave plasma discharge in a rectangular cavity is introduced simply based on surface plasmon polariton theory. The distribution of surface-wave electric field at the interface of the plasma-dielectric slab is investigated by using the three-dimensional finite-difference time-domain method (3D-FDTD) with different slotantenna structures. And the experimental image of discharge with a novel slot antenna array and the simulation of the electric field with this slot antenna array are both displayed. Combined with the distribution of surface wave excitation and experimental results, the numerical simulation performed by using 3D-FDTD is shown to be a useful tool in the computer-aided antenna design for large area planar-type surface-wave plasma sources.展开更多
A self-consistent and three-dimensional (3D) model of argon discharge in a large-scale rectangular surface-wave plasma (SWP) source is presented in this paper, which is based on the finite-difference time-domain ...A self-consistent and three-dimensional (3D) model of argon discharge in a large-scale rectangular surface-wave plasma (SWP) source is presented in this paper, which is based on the finite-difference time-domain (FDTD) approximation to Maxwell's equations self-consistently coupled with a fluid model for plasma evolution. The discharge characteristics at an input microwave power of 1200 W and a filling gas pressure of 50 Pa in the SWP source are analyzed. The simulation shows the time evolution of deposited power density at different stages, and the 3D distributions of electron density and temperature in the chamber at steady state. In addition, the results show that there is a peak of plasma density approximately at a vertical distance of 3 cm from the quartz window.展开更多
In this paper, we show theoretically and experimentally that the large-area planar plasma with high density and good uniformity can be sustained by a surface microwave when the electron density is over-dense. From the...In this paper, we show theoretically and experimentally that the large-area planar plasma with high density and good uniformity can be sustained by a surface microwave when the electron density is over-dense. From the experimental results we find that the nonuniformities in azimuthal plasma density and electron temperature have been greatly improved and in particular the nonuniformity is less than 10% when the gas pressure is 30 Pa. By improving the antenna shape, enhancing the microwave power and choosing the appropriate gas pressure, the large area planar plasma with high density can be produced.展开更多
A three-dimensional fluid model for surface-wave plasma (SWP), to investigate the discharge characteristics of a rectangular SWP source working in a steady state, was presented. The simulation is performed for diffe...A three-dimensional fluid model for surface-wave plasma (SWP), to investigate the discharge characteristics of a rectangular SWP source working in a steady state, was presented. The simulation is performed for different gas pressures in argon and different deposited powers. The results showed that there is a peak of plasma density at a distance of 2 cm to 3 cm from the plasma-quartz interface whose position depends mainly on the gas pressure but not the deposited power. The spatial distributions of plasma parameters and their dependence on the gas pressure and deposited power are also presented and discussed. Using this model a good agreement between the simulation results and the available experimental data is obtained.展开更多
In order to study the influence of nitrogen incorporated into amorphous carbon films, nitrogenated amorphous carbon films have been deposited by using surface wave plasma chemical vapor deposition under various ratios...In order to study the influence of nitrogen incorporated into amorphous carbon films, nitrogenated amorphous carbon films have been deposited by using surface wave plasma chemical vapor deposition under various ratios of N2/CH4 gas flow. Optical emission spectroscopy has been used to monitor plasma features near the deposition zone. After deposition, the samples are checked by Raman spectroscopy and x-ray photo spectroscopy (XPS). Optical emission intensities of CH and N atom in the plasma are found to be enhanced with the increase in the N2/CH4 gas flow ratio, and then reach their maximums when the N2/CH4 gas flow ratio is 5%. A contrary variation is found in Raman spectra of deposited films. The intensity ratio of the D band to the G band (Id/Ig) and the peak positions of the G and D bands all reach their minimums when the N2/CH4 gas flow ratio is 5%. These show that the structure of amorphous carbon films has been significantly modified by introduction of nitrogen.展开更多
The coaxial surface wave linear plasma with preeminent axial uniformity is developed with the 2.45 GHz microwave generator.By optical emission spectroscopy,parameters of the argon linear plasma with a length over 600 ...The coaxial surface wave linear plasma with preeminent axial uniformity is developed with the 2.45 GHz microwave generator.By optical emission spectroscopy,parameters of the argon linear plasma with a length over 600 mm are diagnosed under gas pressure of 30 and 50 Pa and different microwave powers.The spectral lines of argon and Hβ(486.1 nm)atoms in excited state are observed for estimating electron excitation temperature and electron density.Spectrum bands in305–310 nm of diatomic OH(Σ-Π+A X22 i)radicals are used to determine the molecule rotational temperature.Finally,the axial uniformity of electron density and electron excitation temperature are analyzed emphatically under various conditions.The results prove the distinct optimization of compensation from dual powers input,which can narrow the uniform coefficient of electron density and electron excitation temperature by around 40%and 22%respectively.With the microwave power increasing,the axial uniformity of both electron density and electron excitation temperature performs better.Nevertheless,the fluctuation of electron density along the axial direction appeared with higher gas pressure.The axial uniformity of coaxial surface wave linear plasma could be controlled by pressure and power for a better utilization in material processing.展开更多
The resonant absorption of a plasma surface wave is supposed to be an important and efficient mechanism of power deposition for a surface wave plasma source. In this paper, by using the particle-in-cell method and Mon...The resonant absorption of a plasma surface wave is supposed to be an important and efficient mechanism of power deposition for a surface wave plasma source. In this paper, by using the particle-in-cell method and Monte Carlo simulation, the resonance absorption mechanism is investigated. Simulation results demonstrate the existence of surface wave resonance and show the high efficiency of heating electrons. The positions of resonant points, the resonance width and the spatio-temporal evolution of the resonant electric field are presented, which accord well with the theoretical results. The paper also discusses the effect of pressure on the resonance electric field and the plasma density.展开更多
Particles can be removed from a silicon surface by means of irradiation and a laser plasma shock wave.The particles and silicon are heated by the irradiation and they will expand differently due to their different exp...Particles can be removed from a silicon surface by means of irradiation and a laser plasma shock wave.The particles and silicon are heated by the irradiation and they will expand differently due to their different expansion coefficients,making the particles easier to be removed.Laser plasma can ionize and even vaporize particles more significantly than an incident laser and,therefore,it can remove the particles more efficiently.The laser plasma shock wave plays a dominant role in removing particles,which is attributed to its strong burst force.The pressure of the laser plasma shock wave is determined by the laser pulse energy and the gap between the focus of laser and substrate surface.In order to obtain the working conditions for particle removal,the removal mechanism,as well as the temporal and spatial characteristics of velocity,propagation distance and pressure of shock wave have been researched.On the basis of our results,the conditions for nano-particle removal are achieved.展开更多
The excitation of electrostatic surface waves on a semibounded quantum plasma-vacuum interface parallel to an applied magnetic field with electron-hole degeneracy is investigated. The wave equations of the electrostat...The excitation of electrostatic surface waves on a semibounded quantum plasma-vacuum interface parallel to an applied magnetic field with electron-hole degeneracy is investigated. The wave equations of the electrostatic potential and both of the perturbed electron and hole plasma densities have been solved analytically. By using quantum hydrodynamic (QHD) model and the Poisson’s equation with appropriate boundary conditions, the general dispersion relation of these surface modes has been obtained. It is also solved and studied numerically for different cases of plasmas (magnetized or unmagnetized, classical or quantum). We have found that the density ratio of hole-electron plasma plays essential role on the dispersion of the modes along the wavelength beside the quantum and magnetic field.展开更多
Surface wave plasma(SWP) is a kind of low temperature plasma which can be utilized for material development.In this research,argon and oxygen were used as a working gas for an SWP experiment and the influence of the p...Surface wave plasma(SWP) is a kind of low temperature plasma which can be utilized for material development.In this research,argon and oxygen were used as a working gas for an SWP experiment and the influence of the plasma irradiation on a copper surface was examined.Particular,relation between the spatial characteristics of SWP and wetting characteristics was examined.As a result,it was found that spatial characteristics of the SWP affected the wetting characteristics and the oxidation characteristics.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11105002)the Open-end Fund of State Key Laboratory of Structural Analysis for Industrial Equipment,China(Grant No.GZ1215)+1 种基金the Natural Science Foundation for University in Anhui Province of China(Grant No.KJ2013A106)the Doctoral Scientific Research Funds of Anhui University of Science and Technology,China
文摘We analyze the electromagnetic interaction between local surface plasmon polaritons (SPPs) and an atmospheric surface wave plasma jet (ASWPJ) in combination with our designed discharge device. Before discharge, the excitation of the SPPs and the spatial distribution of the enhanced electric field are analyzed. During discharge, the critical breakdown electric field of the gases at atmospheric gas pressure and the surface wave of the SPPs converted into electron plasma waves at resonant points are studied. After discharge, the ionization development process of the ASWPJ is simulated using a two- dimensional fluid model. Our results suggest that the local enhanced electric field of SPPs is merely the precondition of gas breakdown, and the key mechanism in maintaining the discharge development of a low-power ASWPJ is the wave-mode conversion of the local enhanced electric field at the resonant point.
基金the Equipment Foundation of Equipment Ministry of China(No.51421KG0152)
文摘A novel plasma limiter, in which the plasma is excited by surface wave, is presented. The breakdown time of some gases filled in the limiter were calculated as a function of gas pres- sure, ionization degree and density of seed electrons under low pressure (0.01 -1 Torr) and high pressure (10 -1000 Torr) cases. The results show that the limiter filled with Xe with a pressure of 0.9 Torr, seed electron density of 10^16 m^-3, and ionization degree of 10^-4, has a breakdown time of approximate 19.6 ns.
文摘Catalyst-free graphene films has been synthesized by microwave (MW) surface wave plasma (SWP) chemical vapor deposition (CVD) using hydrogenated carbon source on silicon substrates at low temperature (500℃). The synthesized process is simple, low-cost and possible for application on transparent electrodes, gas sensors and thin film resistors. Analytical methods such as Raman spectroscopy, transmission electron microscopy (TEM) and four points prove resistivity measurement and UV-VIS-NIR spectroscopy were employed to characterize properties of the graphene films. The formation of multilayer of graphene on silicon substrate was confirmed by Raman spectroscopy and TEM. It is possible to grow graphene directly on silicon substrate (without using catalyst) due to high radical density of MW SWP CVD. In addition, we also observed that the hydrogen had significant role for quality of graphene.
基金supported by National Natural Science Foundation of China(Nos.11005021,51177017 and 11175049)the Fudan University Excellent Doctoral Research Program(985 Project)the Ph.D Programs Foundation of Ministry of Education of China(No.20120071110031)
文摘An improved surface wave plasma source equipped with a cylindrical quartz rod has been developed, which has great potential in processing inner wall of cylindrical workpieces. A cylindrical quartz rod not only excites the plasma around the rod, but also guides surface wave plasma along the rod. The distributions of plasma density and plasma temperature under different incident microwave powers and pressures are diagnosed by a Langmuir probe. The electron density near the rod is around the order of 10^11cm^-3. When the incident power is 450 W, the length of surface wave plasma column can reach up to 420 mm at 20 Pa.
基金supported in part by National Natural Science of Foundation of China(Nos.11005021,51177017 and 11175049)the Grants-in-Aid for Scientific Research of Japan Society for the Promotion of Science(No.21110010)+1 种基金the Fudan University Excellent Doctoral Research Program(985 project)the Ph.D Programs Foundation of Ministry of Education of China(No.20120071110031)
文摘A novel surface wave plasma (SWP) source excited with cylindrical Teflon waveguide has been developed in our previous work. The plasma characteristics have been simply studied. In this work, our experimental device has been significantly improved by replacing the Teflon waveguide with a quartz rod, and then better microwave coupling and higher gas purity can be obtained during plasma discharge. The plasma spatial distributions, both in radial and axial directions, have been measured and the effect of gas pressure has been investigated. Plasma density profiles indicate that this plasma source can produce uniform plasma in an axial direction at low pressure, which shows its potential in plasma processing on a curved surface such as an inner tube wall. A simplified circular waveguide model has been used to explain the principle of plasma excitation. The distinguishing features and potential application of this kind of plasma source with a hardware improvement have been shown.
基金supported by the Foundation for Returned Scholars,the Ministry of Education of China
文摘The principle of surface wave plasma discharge in a rectangular cavity is introduced simply based on surface plasmon polariton theory. The distribution of surface-wave electric field at the interface of the plasma-dielectric slab is investigated by using the three-dimensional finite-difference time-domain method (3D-FDTD) with different slotantenna structures. And the experimental image of discharge with a novel slot antenna array and the simulation of the electric field with this slot antenna array are both displayed. Combined with the distribution of surface wave excitation and experimental results, the numerical simulation performed by using 3D-FDTD is shown to be a useful tool in the computer-aided antenna design for large area planar-type surface-wave plasma sources.
基金Project supported by the Special Fund of National High-Tech Development and Research Plan (Grant No 2008AA12A214)
文摘A self-consistent and three-dimensional (3D) model of argon discharge in a large-scale rectangular surface-wave plasma (SWP) source is presented in this paper, which is based on the finite-difference time-domain (FDTD) approximation to Maxwell's equations self-consistently coupled with a fluid model for plasma evolution. The discharge characteristics at an input microwave power of 1200 W and a filling gas pressure of 50 Pa in the SWP source are analyzed. The simulation shows the time evolution of deposited power density at different stages, and the 3D distributions of electron density and temperature in the chamber at steady state. In addition, the results show that there is a peak of plasma density approximately at a vertical distance of 3 cm from the quartz window.
文摘In this paper, we show theoretically and experimentally that the large-area planar plasma with high density and good uniformity can be sustained by a surface microwave when the electron density is over-dense. From the experimental results we find that the nonuniformities in azimuthal plasma density and electron temperature have been greatly improved and in particular the nonuniformity is less than 10% when the gas pressure is 30 Pa. By improving the antenna shape, enhancing the microwave power and choosing the appropriate gas pressure, the large area planar plasma with high density can be produced.
文摘A three-dimensional fluid model for surface-wave plasma (SWP), to investigate the discharge characteristics of a rectangular SWP source working in a steady state, was presented. The simulation is performed for different gas pressures in argon and different deposited powers. The results showed that there is a peak of plasma density at a distance of 2 cm to 3 cm from the plasma-quartz interface whose position depends mainly on the gas pressure but not the deposited power. The spatial distributions of plasma parameters and their dependence on the gas pressure and deposited power are also presented and discussed. Using this model a good agreement between the simulation results and the available experimental data is obtained.
基金Natural Science Foundation of Anhui Province(No.03044702)National Natural Science Foundation of China(No.19835030)
文摘In order to study the influence of nitrogen incorporated into amorphous carbon films, nitrogenated amorphous carbon films have been deposited by using surface wave plasma chemical vapor deposition under various ratios of N2/CH4 gas flow. Optical emission spectroscopy has been used to monitor plasma features near the deposition zone. After deposition, the samples are checked by Raman spectroscopy and x-ray photo spectroscopy (XPS). Optical emission intensities of CH and N atom in the plasma are found to be enhanced with the increase in the N2/CH4 gas flow ratio, and then reach their maximums when the N2/CH4 gas flow ratio is 5%. A contrary variation is found in Raman spectra of deposited films. The intensity ratio of the D band to the G band (Id/Ig) and the peak positions of the G and D bands all reach their minimums when the N2/CH4 gas flow ratio is 5%. These show that the structure of amorphous carbon films has been significantly modified by introduction of nitrogen.
基金supported by National Natural Science Foundation of China(Nos.11575252 and 11775270)Institute of Energy of Hefei Comprehensive National Science Center,People’s Republic of China(Nos.19KZS206,21KZS201)。
文摘The coaxial surface wave linear plasma with preeminent axial uniformity is developed with the 2.45 GHz microwave generator.By optical emission spectroscopy,parameters of the argon linear plasma with a length over 600 mm are diagnosed under gas pressure of 30 and 50 Pa and different microwave powers.The spectral lines of argon and Hβ(486.1 nm)atoms in excited state are observed for estimating electron excitation temperature and electron density.Spectrum bands in305–310 nm of diatomic OH(Σ-Π+A X22 i)radicals are used to determine the molecule rotational temperature.Finally,the axial uniformity of electron density and electron excitation temperature are analyzed emphatically under various conditions.The results prove the distinct optimization of compensation from dual powers input,which can narrow the uniform coefficient of electron density and electron excitation temperature by around 40%and 22%respectively.With the microwave power increasing,the axial uniformity of both electron density and electron excitation temperature performs better.Nevertheless,the fluctuation of electron density along the axial direction appeared with higher gas pressure.The axial uniformity of coaxial surface wave linear plasma could be controlled by pressure and power for a better utilization in material processing.
文摘The resonant absorption of a plasma surface wave is supposed to be an important and efficient mechanism of power deposition for a surface wave plasma source. In this paper, by using the particle-in-cell method and Monte Carlo simulation, the resonance absorption mechanism is investigated. Simulation results demonstrate the existence of surface wave resonance and show the high efficiency of heating electrons. The positions of resonant points, the resonance width and the spatio-temporal evolution of the resonant electric field are presented, which accord well with the theoretical results. The paper also discusses the effect of pressure on the resonance electric field and the plasma density.
基金Project supported by the National Natural Science Foundation of China(Grant No.11574221)
文摘Particles can be removed from a silicon surface by means of irradiation and a laser plasma shock wave.The particles and silicon are heated by the irradiation and they will expand differently due to their different expansion coefficients,making the particles easier to be removed.Laser plasma can ionize and even vaporize particles more significantly than an incident laser and,therefore,it can remove the particles more efficiently.The laser plasma shock wave plays a dominant role in removing particles,which is attributed to its strong burst force.The pressure of the laser plasma shock wave is determined by the laser pulse energy and the gap between the focus of laser and substrate surface.In order to obtain the working conditions for particle removal,the removal mechanism,as well as the temporal and spatial characteristics of velocity,propagation distance and pressure of shock wave have been researched.On the basis of our results,the conditions for nano-particle removal are achieved.
文摘The excitation of electrostatic surface waves on a semibounded quantum plasma-vacuum interface parallel to an applied magnetic field with electron-hole degeneracy is investigated. The wave equations of the electrostatic potential and both of the perturbed electron and hole plasma densities have been solved analytically. By using quantum hydrodynamic (QHD) model and the Poisson’s equation with appropriate boundary conditions, the general dispersion relation of these surface modes has been obtained. It is also solved and studied numerically for different cases of plasmas (magnetized or unmagnetized, classical or quantum). We have found that the density ratio of hole-electron plasma plays essential role on the dispersion of the modes along the wavelength beside the quantum and magnetic field.
文摘Surface wave plasma(SWP) is a kind of low temperature plasma which can be utilized for material development.In this research,argon and oxygen were used as a working gas for an SWP experiment and the influence of the plasma irradiation on a copper surface was examined.Particular,relation between the spatial characteristics of SWP and wetting characteristics was examined.As a result,it was found that spatial characteristics of the SWP affected the wetting characteristics and the oxidation characteristics.