中国物理B ›› 2011, Vol. 20 ›› Issue (7): 78103-078103.doi: 10.1088/1674-1056/20/7/078103

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Growth of gem-grade nitrogen-doped diamond crystals heavily doped with the addition of Ba(N3)2

黄国锋, 贾晓鹏, 李勇, 胡美华, 李战厂, 颜丙敏, 马红安   

  1. National Laboratory of Superhard Materials, Jilin University, Changchun 130012, China
  • 收稿日期:2010-11-14 修回日期:2011-03-04 出版日期:2011-07-15 发布日期:2011-07-15

Growth of gem-grade nitrogen-doped diamond crystals heavily doped with the addition of Ba(N3)2

Huang Guo-Feng(黄国锋), Jia Xiao-Peng(贾晓鹏), Li Yong(李勇), Hu Mei-Hua(胡美华), Li Zhan-Chang(李战厂), Yan Bing-Min(颜丙敏), and Ma Hong-An(马红安)†   

  1. National Laboratory of Superhard Materials, Jilin University, Changchun 130012, China
  • Received:2010-11-14 Revised:2011-03-04 Online:2011-07-15 Published:2011-07-15

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摘要： Additive Ba(N3)2 as a source of nitrogen is heavily doped into the graphite—Fe-based alloy system to grow nitrogen-doped diamond crystals under a relatively high pressure (about 6.0 GPa) by employing the temperature gradient method. Gem-grade diamond crystal with a size of around 5 mm and a nitrogen concentration of about 1173 ppm is successfully synthesised for the first time under high pressure and high temperature in a China-type cubic anvil high-pressure apparatus. The growth habit of diamond crystal under the environment with high degree of nitrogen doping is investigated. It is found that the morphologies of heavily nitrogen-doped diamond crystals are all of octahedral shape dominated by 111 facets. The effects of temperature and duration on nitrogen concentration and form are explored by infrared absorption spectra. The results indicate that nitrogen impurity is present in diamond predominantly in the dispersed form accompanied by aggregated form, and the aggregated nitrogen concentration in diamond increases with temperature and duration. In addition, it is indicated that nitrogen donors are more easily incorporated into growing crystals at higher temperature. Strains in nitrogen-doped diamond crystal are characterized by micro-Raman spectroscopy. Measurement results demonstrate that the undoped diamond crystals exhibit the compressive stress, whereas diamond crystals heavily doped with the addition of Ba(N3)2 display the tensile stress.

关键词: temperature gradient method, gem-grade nitrogen-doped diamond crystals, high temperature and high pressure, additive Ba(N3)2

Abstract: Additive Ba(N3)2 as a source of nitrogen is heavily doped into the graphite—Fe-based alloy system to grow nitrogen-doped diamond crystals under a relatively high pressure (about 6.0 GPa) by employing the temperature gradient method. Gem-grade diamond crystal with a size of around 5 mm and a nitrogen concentration of about 1173 ppm is successfully synthesised for the first time under high pressure and high temperature in a China-type cubic anvil high-pressure apparatus. The growth habit of diamond crystal under the environment with high degree of nitrogen doping is investigated. It is found that the morphologies of heavily nitrogen-doped diamond crystals are all of octahedral shape dominated by {111} facets. The effects of temperature and duration on nitrogen concentration and form are explored by infrared absorption spectra. The results indicate that nitrogen impurity is present in diamond predominantly in the dispersed form accompanied by aggregated form, and the aggregated nitrogen concentration in diamond increases with temperature and duration. In addition, it is indicated that nitrogen donors are more easily incorporated into growing crystals at higher temperature. Strains in nitrogen-doped diamond crystal are characterized by micro-Raman spectroscopy. Measurement results demonstrate that the undoped diamond crystals exhibit the compressive stress, whereas diamond crystals heavily doped with the addition of Ba(N3)2 display the tensile stress.

Key words: temperature gradient method, gem-grade nitrogen-doped diamond crystals, high temperature and high pressure, additive Ba(N3)2

中图分类号:  (Growth from melts; zone melting and refining)

  • 81.10.Fq
61.72.S- (Impurities in crystals) 64.70.dg (Crystallization of specific substances) 07.57.Ty (Infrared spectrometers, auxiliary equipment, and techniques)