The electrical and plasma parameters of a low pressure inductively coupled argon plasma are investigated over a wide range of parameters（RF power, flow rate and pressure） by diverse characterizations. The external a...The electrical and plasma parameters of a low pressure inductively coupled argon plasma are investigated over a wide range of parameters（RF power, flow rate and pressure） by diverse characterizations. The external antenna voltage and current increase with the augment of RF power, whereas decline with the enhancement of gas pressure and flow rate conversely.Compared with gas flow rate and pressure, the power transfer efficiency is significantly improved by RF power, and achieved its maximum value of 0.85 after RF power injected excess125 W. Optical emission spectroscopy（OES） provides the local mean values of electron excited temperature and electron density in inductively coupled plasma（ICP） post regime, which vary in a range of 0.81 eV to 1.15 eV and 3.7×10^（16）m^（-3）to 8.7×10^（17）m^（-3）respectively. Numerical results of the average magnitudes of electron temperature and electron density in twodimensional distribution exhibit similar variation trend with the experimental results under different operating condition by using COMSOL Multiphysics. By comprehensively understanding the characteristics in a low pressure ICP, optimized operating conditions could be anticipated aiming at different academic and industrial applications.展开更多
One-step controllable synthesis of vertical graphene nanosheets （VGs） and high-value gases was achieved using inductively coupled plasma enhanced chemical vapor deposition （ICPECVD）. The basic physical properties ...One-step controllable synthesis of vertical graphene nanosheets （VGs） and high-value gases was achieved using inductively coupled plasma enhanced chemical vapor deposition （ICPECVD）. The basic physical properties of the ICPECVD process were revealed via electrical diagnosis and optical emission spectroscopy. The coil current and voltage increased linearly with the augmenting of injected power, and CH, C2, H2 and H were detected at a wavelength from 300 to 700 nm, implying the generation of abundant graphene-building species. The morphology and structure of solid carbon products, graphene nanosheets, were systemically characterized in terms of the variations of operating conditions, such as pressure, temperature, gas proportion, etc. The results indicated that an appropriate operating condition was indispensable for the growth process of graphene nanosheets. In the present work, the optimized result was achieved at the pressure, heating temperature, applied power and gas proportion of 600 mTorr, 800 ~C, 500 W and 20：20：15, respectively, and the augmenting of both CH4 and H2 concentrations had a positive effect on the etching of amorphous carbon. Additionally, H2 and C2 hydrocarbons were detected as the main exhaust gases. The selectivity of H2 and C2H2, measured in exhaust gases, reached up to 52% and 8%, respectively, which implied a process of free radical reactions and electron collision dissociation. Based on a comprehensive investigation of spectral and electrical parameters and synthesized products, the reaction mechanism of collision, dissociation, diffusion, etc, in ICPECVD could be speculated, providing a probable guide for experimental and industrial applications.展开更多
基金supported by National Natural Science Foundation of China(No.51576174)
文摘The electrical and plasma parameters of a low pressure inductively coupled argon plasma are investigated over a wide range of parameters（RF power, flow rate and pressure） by diverse characterizations. The external antenna voltage and current increase with the augment of RF power, whereas decline with the enhancement of gas pressure and flow rate conversely.Compared with gas flow rate and pressure, the power transfer efficiency is significantly improved by RF power, and achieved its maximum value of 0.85 after RF power injected excess125 W. Optical emission spectroscopy（OES） provides the local mean values of electron excited temperature and electron density in inductively coupled plasma（ICP） post regime, which vary in a range of 0.81 eV to 1.15 eV and 3.7×10^（16）m^（-3）to 8.7×10^（17）m^（-3）respectively. Numerical results of the average magnitudes of electron temperature and electron density in twodimensional distribution exhibit similar variation trend with the experimental results under different operating condition by using COMSOL Multiphysics. By comprehensively understanding the characteristics in a low pressure ICP, optimized operating conditions could be anticipated aiming at different academic and industrial applications.
基金supported by National Natural Science Foundation of China(No.51576174)China Postdoctoral Science Foundation Funded Project(No.2018M630672)
文摘One-step controllable synthesis of vertical graphene nanosheets （VGs） and high-value gases was achieved using inductively coupled plasma enhanced chemical vapor deposition （ICPECVD）. The basic physical properties of the ICPECVD process were revealed via electrical diagnosis and optical emission spectroscopy. The coil current and voltage increased linearly with the augmenting of injected power, and CH, C2, H2 and H were detected at a wavelength from 300 to 700 nm, implying the generation of abundant graphene-building species. The morphology and structure of solid carbon products, graphene nanosheets, were systemically characterized in terms of the variations of operating conditions, such as pressure, temperature, gas proportion, etc. The results indicated that an appropriate operating condition was indispensable for the growth process of graphene nanosheets. In the present work, the optimized result was achieved at the pressure, heating temperature, applied power and gas proportion of 600 mTorr, 800 ~C, 500 W and 20：20：15, respectively, and the augmenting of both CH4 and H2 concentrations had a positive effect on the etching of amorphous carbon. Additionally, H2 and C2 hydrocarbons were detected as the main exhaust gases. The selectivity of H2 and C2H2, measured in exhaust gases, reached up to 52% and 8%, respectively, which implied a process of free radical reactions and electron collision dissociation. Based on a comprehensive investigation of spectral and electrical parameters and synthesized products, the reaction mechanism of collision, dissociation, diffusion, etc, in ICPECVD could be speculated, providing a probable guide for experimental and industrial applications.
