采用粒子群优化算法的结构预测程序CALYPSO结合基于密度泛函理论的VASP软件包对B6C6N6进行结构预测, 得到新的二维BCN结构, 该结构由6个B、6个C、6个N组成类石墨烯六角结构, 其中B—N、B—C—N以及C—C之间形成的六环是稳定BCN结构的关键。凝聚能和声子谱计算结果表明二维BCN在热力学和动力学上均是稳定的。能带结构和电子态密度的计算分析表明BCN是禁带宽度为2.60 eV直接带隙半导体。基于形变势理论, 计算了BCN新结构的载流子迁移率, 发现BCN在“之”字边和“扶手”边方向上的电子迁移率分别为632.5, 923.3 cm2·V-1·s-1, 而空穴在两个方向上的迁移率分别为765.7, 622.6 cm2·V-1·s-1, 迁移率的值明显高于MoS2的载流子迁移率, 相对较高的迁移率说明二维BCN具有较好的输运性质。光学性质的计算研究表明BCN的介电函数虚部峰值同吸收谱和光电导率的实部峰值吻合得很好, 可见光范围内的吸收峰位于光子能量～2.61 eV处, 可见光范围内的吸收主要归因于电子从价带顶到导带底的跃迁。本研究结果为实验上实现原子比为6∶6∶6的BCN的制备以及BCN在光电器件方面的应用提供了重要的理论依据。

By means of the particle swarm optimization algorithm and density functional theory on two dimensional B6C6N6 structure prediction, we predicted that the lower-energy structure of BCN monolayer composed of C6, B3N3, and B2C2N2 ring, is vital to structural stability. The calculation of cohesive energy and phonon spectra indicate that the BCN is stable thermally and dynamically, respectively. Our HSE06 calculation shows that BCN is a direct-gap semiconductor with a band-gap of 2.60 eV. Furthermore, based on the deformation potential theory, the BCN monolayer has electron mobility (632.5 cm2·V-1·s-1along “zigzag” direction and 923.3 cm2·V-1·s-1 along “armchair” direction, respectively) and hole mobility (765.7 cm2·V-1·s-1 along “zigzag” direction and 622.6 cm2·V-1·s-1along “armchair” direction, respectively), higher than that of MoS2. The higher carrier mobility indicates that BCN has good transport property. The calculation of optical properties shows that the peak of dielectric function of BCN is in good agreement with the peak of absorption spectrum and photoconductivity. The absorption peak in the visible light range is located at the photon energy of ~2.61 eV, which mainly originates the electron transition from the valence band maximum to the conduction band minimum. The results of this study provide a theoretical basis for the application of BCN in optoelectronic devices.