硼掺杂和氮掺杂金刚石的吸附生长过程研究

Study on the Adsorption Growth Process of B-doped and N-doped Diamonds

采用基于密度泛函理论的第一性原理平面波赝势方法,探究了化学气相沉积硼掺杂和氮掺杂金刚石的吸附生长过程:建立了一端为氢终止表面的金刚石基底模型以及单个氮取代或单个硼取代的掺杂金刚石基底模型,并计算这些模型的最优稳定结构;研究了不同碳氢基团(C、CH、CH2、CH3)、硼氢基团(B、BH、BH2)和氮氢基团(N、NH、NH2)在有活性位点的不同基底上的吸附过程和吸附难易程度。对比计算结果表明:硼原子和氮原子能通过原位取代的方式掺杂进入金刚石晶格中,并且带有两个氢的基团(BH2、NH2)是最有利的掺杂基团;氮原子通过取代进入金刚石晶格中后,难以形成氮二聚体,不能大量掺杂,而硼原子较易形成硼二聚体,可以实现大量掺杂。

The growth and deposition process of chemical vapor deposition boron-doped and nitrogen-doped diamond were explored by the first-principles plane wave pseudo-potential method based on density functional theory.The diamond substrate model with hydrogen termination surface and single nitrogen-substituted or single boron-substituted were established,and the optimal stable structure of these models was calculated.The adsorption process and the adsorption difficulty of different hydrocarbon groups(C,CH,CH2,and CH3),boron-hydrogen groups(B,BH,and BH2)and nitrogen-hydrogen groups(N,NH,NH2)on different substrates with active site were studied.The results show that boron atoms and nitrogen atoms can be doped into the diamond lattice by in-situ substitution,and the two-hydrogen-bearing groups(BH2,NH2)are the most favorable doping groups.The nitrogen atom is difficult to form a nitrogen dimer after substitution into the diamond crystal lattice,which cannot be heavily doped,but the boron atom is more likely to form a boron dimer,so its heavy doping can be achieved.