Monte Carlo simulations are adopted to study the electron motion in the mixture of H2 and CH4 during diamond synthesis via Glow Plasma-assisted Chemical Vapor Deposition (GPCVD). The non-uniform electric field is used...Monte Carlo simulations are adopted to study the electron motion in the mixture of H2 and CH4 during diamond synthesis via Glow Plasma-assisted Chemical Vapor Deposition (GPCVD). The non-uniform electric field is used and the avalanche of electrons is taken into account in this simulation. The average energy distribution of electrons and the space distribution of effective species such as CH3, CH+3, CH+ and H at various gas pressures are given in this paper, and optimum experimental conditions are inferred from these results.展开更多
A Molecular Dynamics (MD) simulation with Tersoff empirical many-bodypotential has been employed to investigate the growth processes of diamond film with energeticspecies deposition. In the present study, we have stud...A Molecular Dynamics (MD) simulation with Tersoff empirical many-bodypotential has been employed to investigate the growth processes of diamond film with energeticspecies deposition. In the present study, we have studied the reaction probabilities of energeticspecies with energies of 0.1 e V to 10eV at the substrate temperature of 1100K. In the cases of thediamond growth on the surface with H passivation, the reaction probability of hydrocarbon speciesconsiderably increases when the species energy is higher than 2eV. This means that the diamond filmcan grow in the case of high incident species energy without the process of hydrogen abstraction,which is needed in the case of incident species with low energy. The reaction mechanism of energeticspecies on hydrogen passivated diamond surface is also discussed.展开更多
A free-standing diamond film with millimeter thickness prepared by DC arc plasma jet was thinned successively by mechanical grinding. The orientation and quality of the diamond films with different thicknesses were ch...A free-standing diamond film with millimeter thickness prepared by DC arc plasma jet was thinned successively by mechanical grinding. The orientation and quality of the diamond films with different thicknesses were characterized by X-ray diffraction and Raman spectroscopy, respectively. The results show a random grain-orientatinn distribution during the initial growth stage. As the film thickness increases, the preferred orientation of the diamond film changes from （111） to （220）, due to the competitive growth mechanism. Twinning generated during the nucleation stage appears to stabilize the preferential growth along the 〈110〉 direction. The interplanar spacing of the （220） plane is enlarged as the film thickness increases, which is caused by the increase of non-diamond-phase carbon and impurities under the cyclic gas. In addition, the quality of the diamond film is barely degraded during the growth process. Furthermore, the peak shift demonstrates a significant inhomogeneity of stress along the film growth direction, which results from competitive growth.展开更多
With H_2 and CH_3COCH_3 used as the source gases,the diamond epitaxlal films were obtained on the sythe siged single-crystal diamond(100),(110)and(111)faces by means of the microwave plasma-assisted chemical-vapor-dep...With H_2 and CH_3COCH_3 used as the source gases,the diamond epitaxlal films were obtained on the sythe siged single-crystal diamond(100),(110)and(111)faces by means of the microwave plasma-assisted chemical-vapor-deposition (CVD) method. Epitaxlal growth spirals and growth steps can be observed by scanning electron micrographs. Using micro Raman spectra method,we analysed the contents of graphites and other forms of carbon in the single-crystal diamond thin films.The experimental results showed that there are no other forms of carbon in the epitaxial films.Analysis results of reflection electron diffraction showed that the epitaxial diainond film s on diamond(100)an(110)Surfaces are single-crystal diamond films.展开更多
基金This work was supported by Doctor Foundation of Hebei Education Committee Hebei Natural Science Foundation(599091 ) of China
文摘Monte Carlo simulations are adopted to study the electron motion in the mixture of H2 and CH4 during diamond synthesis via Glow Plasma-assisted Chemical Vapor Deposition (GPCVD). The non-uniform electric field is used and the avalanche of electrons is taken into account in this simulation. The average energy distribution of electrons and the space distribution of effective species such as CH3, CH+3, CH+ and H at various gas pressures are given in this paper, and optimum experimental conditions are inferred from these results.
基金This work is supported by the National Natural Science Foundation (Grant No. 10075009) Sino-France Advance Research Program (PRA)
文摘A Molecular Dynamics (MD) simulation with Tersoff empirical many-bodypotential has been employed to investigate the growth processes of diamond film with energeticspecies deposition. In the present study, we have studied the reaction probabilities of energeticspecies with energies of 0.1 e V to 10eV at the substrate temperature of 1100K. In the cases of thediamond growth on the surface with H passivation, the reaction probability of hydrocarbon speciesconsiderably increases when the species energy is higher than 2eV. This means that the diamond filmcan grow in the case of high incident species energy without the process of hydrogen abstraction,which is needed in the case of incident species with low energy. The reaction mechanism of energeticspecies on hydrogen passivated diamond surface is also discussed.
基金financially supported by the National Natural Science Foundation of China (No. 51272024)the Ph.D. Programs Foundation of the Ministry of Education of China (No. 20110006110011)the Fundamental Research Funds for Central Universities of China (No. FRF-TP-13-035A)
文摘A free-standing diamond film with millimeter thickness prepared by DC arc plasma jet was thinned successively by mechanical grinding. The orientation and quality of the diamond films with different thicknesses were characterized by X-ray diffraction and Raman spectroscopy, respectively. The results show a random grain-orientatinn distribution during the initial growth stage. As the film thickness increases, the preferred orientation of the diamond film changes from （111） to （220）, due to the competitive growth mechanism. Twinning generated during the nucleation stage appears to stabilize the preferential growth along the 〈110〉 direction. The interplanar spacing of the （220） plane is enlarged as the film thickness increases, which is caused by the increase of non-diamond-phase carbon and impurities under the cyclic gas. In addition, the quality of the diamond film is barely degraded during the growth process. Furthermore, the peak shift demonstrates a significant inhomogeneity of stress along the film growth direction, which results from competitive growth.
文摘With H_2 and CH_3COCH_3 used as the source gases,the diamond epitaxlal films were obtained on the sythe siged single-crystal diamond(100),(110)and(111)faces by means of the microwave plasma-assisted chemical-vapor-deposition (CVD) method. Epitaxlal growth spirals and growth steps can be observed by scanning electron micrographs. Using micro Raman spectra method,we analysed the contents of graphites and other forms of carbon in the single-crystal diamond thin films.The experimental results showed that there are no other forms of carbon in the epitaxial films.Analysis results of reflection electron diffraction showed that the epitaxial diainond film s on diamond(100)an(110)Surfaces are single-crystal diamond films.
基金National Natural Science Foundation of China(51402013,51272024)China Postdoctoral Science Foundation(2014M550022)Fundamental Research Funds for the Central Universities(FRF-TP-15-052A2)~~
