Optical centers of single-crystal diamond grown by DC arc plasma jet chemical vapor deposition(CVD) were examined using a low-temperature photoluminescence(PL) technique. The results show that most of the nitrogen-vac...Optical centers of single-crystal diamond grown by DC arc plasma jet chemical vapor deposition(CVD) were examined using a low-temperature photoluminescence(PL) technique. The results show that most of the nitrogen-vacancy(NV) complexes are present as NV-centers, although some H2 and H3 centers and B-aggregates are also present in the single-crystal diamond because of nitrogen aggregation resulting from high N_2 incorporation and the high mobility of vacancies under growth temperatures of 950–1000°C. Furthermore, emissions of radiation-induced defects were also detected at 389, 467.5, 550, and 588.6 nm in the PL spectra. The reason for the formation of these radiation-induced defects is not clear. Although a Ni-based alloy was used during the diamond growth, Ni-related emissions were not detected in the PL spectra. In addition, the silicon-vacancy(Si-V)-related emission line at 737 nm, which has been observed in the spectra of many previously reported microwave plasma chemical vapor deposition(MPCVD) synthetic diamonds, was absent in the PL spectra of the single-crystal diamond prepared in this work. The high density of NV-centers, along with the absence of Ni-related defects and Si-V centers, makes the single-crystal diamond grown by DC arc plasma jet CVD a promising material for applications in quantum computing.展开更多
采用直流电弧等离子体蒸发法制备高纯度纳米级硅粉,利用X射线衍射、X射线荧光分析、氮氧分析仪、透射电子显微镜和相应的选区电子衍射等测试手段对样品物理化学性质进行表征。采用紫外分光光度计法研究超声时间和不同的分散剂及其加入...采用直流电弧等离子体蒸发法制备高纯度纳米级硅粉,利用X射线衍射、X射线荧光分析、氮氧分析仪、透射电子显微镜和相应的选区电子衍射等测试手段对样品物理化学性质进行表征。采用紫外分光光度计法研究超声时间和不同的分散剂及其加入量对纳米硅粉在水介质中分散效果的影响。结果表明:制备出近球形、立方晶型结构的纳米硅粉,粒径分布窄,其纯度达到99.93%(质量比)。随着超声时间和分散剂浓度的增加,分散效果呈现先增大后趋向平稳的趋势,十六烷基三甲基溴化铵(CTAB)对纳米硅粉在水介质中的分散效果最好。纳米硅粉在水介质中较好的分散工艺为:在pH=6、超声功率为560 W的情况下,CTAB加入量为4%,超声时间为80 min。分散后的硅粉比未分散的硅粉首次放电比容量提升14.93%,达到了2640 m Ah/g,首次库伦效率达到34.92%。展开更多
基金financially supported by the International Science and Technology Cooperation Program of China (No.2015DFG02100)the National Key Laboratory of Shock Wave and Detonation Physics (LSD) Project (No.YK20150101001)
文摘Optical centers of single-crystal diamond grown by DC arc plasma jet chemical vapor deposition(CVD) were examined using a low-temperature photoluminescence(PL) technique. The results show that most of the nitrogen-vacancy(NV) complexes are present as NV-centers, although some H2 and H3 centers and B-aggregates are also present in the single-crystal diamond because of nitrogen aggregation resulting from high N_2 incorporation and the high mobility of vacancies under growth temperatures of 950–1000°C. Furthermore, emissions of radiation-induced defects were also detected at 389, 467.5, 550, and 588.6 nm in the PL spectra. The reason for the formation of these radiation-induced defects is not clear. Although a Ni-based alloy was used during the diamond growth, Ni-related emissions were not detected in the PL spectra. In addition, the silicon-vacancy(Si-V)-related emission line at 737 nm, which has been observed in the spectra of many previously reported microwave plasma chemical vapor deposition(MPCVD) synthetic diamonds, was absent in the PL spectra of the single-crystal diamond prepared in this work. The high density of NV-centers, along with the absence of Ni-related defects and Si-V centers, makes the single-crystal diamond grown by DC arc plasma jet CVD a promising material for applications in quantum computing.
文摘采用直流电弧等离子体蒸发法制备高纯度纳米级硅粉,利用X射线衍射、X射线荧光分析、氮氧分析仪、透射电子显微镜和相应的选区电子衍射等测试手段对样品物理化学性质进行表征。采用紫外分光光度计法研究超声时间和不同的分散剂及其加入量对纳米硅粉在水介质中分散效果的影响。结果表明:制备出近球形、立方晶型结构的纳米硅粉,粒径分布窄,其纯度达到99.93%(质量比)。随着超声时间和分散剂浓度的增加,分散效果呈现先增大后趋向平稳的趋势,十六烷基三甲基溴化铵(CTAB)对纳米硅粉在水介质中的分散效果最好。纳米硅粉在水介质中较好的分散工艺为:在pH=6、超声功率为560 W的情况下,CTAB加入量为4%,超声时间为80 min。分散后的硅粉比未分散的硅粉首次放电比容量提升14.93%,达到了2640 m Ah/g,首次库伦效率达到34.92%。
