异质结
赝势
电场
带隙
电子结构
物理
凝聚态物理
材料科学
原子物理学
量子力学
作者
刘晨曦,庞国旺,潘多桥,史蕾倩,张丽丽,雷博程,赵旭才,黄以能
出处
期刊:Chinese Physics
[Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences]
日期:2022-01-01
卷期号:71 (9): 097301-097301
标识
DOI:10.7498/aps.71.20212261
摘要
In this paper, the stability, electronic structure, optical properties, and work function of GaN/g-C<sub>3</sub>N<sub>4</sub> heterojunction are studied by using the first-principles plane wave ultra-soft pseudopotential method based on density functional theory. The electric field effect is also considered. The results show that the total energy for each of the three stacking modes changes little for using the two different dispersion correction methods, i.e. Tkatchenko-Scheffler and Grimme, and the total energy of mode II is the lowest, indicating that the structure of mode II is the most stable. The lattice mismatch ratio and lattice mismatch energy of GaN/g-C<sub>3</sub>N<sub>4</sub> van der Waals heterojunction are very low, indicating that the heterojunction has good stability. The heterojunction retains the basic electronic properties of GaN and g-C<sub>3</sub>N<sub>4</sub> to a great extent and can be used as a direct bandgap semiconductor material. It can be known from the work function and differential charge diagram that the charge on the heterojunction interface is transferred from GaN to g-C<sub>3</sub>N<sub>4</sub>, and a built-in electric field orientating g-C<sub>3</sub>N<sub>4</sub> from GaN is formed at the interface. The built-in electric field of the heterojunction can effectively separate the photogenerated electron-hole pairs, which is conducive to improving the photocatalytic capability of the system. Further analysis shows that the applied electric field reduces the bandgap of GaN/g-C<sub>3</sub>N<sub>4</sub> heterostructure to varying degrees. It makes it easier for electrons to transit from valence band to conduction band, which is conducive to improving the photocatalytic activity of the system. In addition, when the applied electric field is –0.6 V/Å and 0.5 V/Å separately, the semiconductor metal phase transition occurs in the heterojunction. When the applied electric field is higher than 0.3 V/Å and lower than –0.4 V/Å, in the energy band arrangement of the heterojunction there occurs the transition from type I to type II. This can better realize the separation of photogenerated electron-hole pairs and further improve the photocatalytic capactivity of the system. Therefore, the construction of heterojunction and application of external electric field proposed in this work constitute an effective means to improve the photocatalytic activity of the system.
科研通智能强力驱动
Strongly Powered by AbleSci AI