Wang Rui, Zhou Liming, Wang Wentao
Henan Key Laboratory of Big Data Analysis and Processing, School of Computer and Information Engineering, Henan University, Kaifeng 475001, China.
Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Education University, Guiyang 550018, China.
ACS Omega. 2023 Jun 2;8(23):21162-21171. doi: 10.1021/acsomega.3c02161. eCollection 2023 Jun 13.
Using the GGA + method, the formation energy and concentration of intrinsic defects in BiMoO are explored under different chemical conditions, with/without doping, from 120 to 900 K. We find that the intrinsic defect and carrier concentration can be deduced from the small range of calculated Fermi levels in the diagram of formation energy vs Fermi level under different conditions. Once the doping conditions or/and temperature are determined, the corresponding is only limited to a special region in the diagram of formation energy vs Fermi level, from which the magnitude relationship of defects concentration can be directly derived from their formation energy. The lower the defect formation energy is, the higher the defect concentration is. With moving under different doping conditions, the intrinsic defect concentration changes accordingly. At the same time, the highest electron concentration at the relative O-poor (point ) with only intrinsic defects confirms its intrinsic n-type behavior. Moreover, upon A/D doping, moves closer to VBM/CBM for the increasing concentration of holes/electrons. The electron concentration can also be further improved after D doping, indicating that D doping under O-poor chemical growth conditions is positive to improve its photogenerated carriers. This provides us with a method to adjust the intrinsic defect concentration and deepens our knowledge about comprehension and application of the diagram of formation energy vs Fermi level.
采用广义梯度近似（GGA）+方法，在120至900K的不同化学条件下（有/无掺杂），研究了钼酸铋（BiMoO）中本征缺陷的形成能和浓度。我们发现，在不同条件下的形成能与费米能级图中，通过计算得到的费米能级范围较小，就可以推导出本征缺陷和载流子浓度。一旦确定了掺杂条件或/和温度，相应的情况在形成能与费米能级图中仅局限于一个特殊区域，从该区域可以直接根据缺陷的形成能得出缺陷浓度的大小关系。缺陷形成能越低，缺陷浓度越高。随着在不同掺杂条件下移动，本征缺陷浓度相应变化。同时，在仅存在本征缺陷的相对贫氧（点）处，最高电子浓度证实了其本征n型行为。此外，进行A/D掺杂时，随着空穴/电子浓度的增加，向价带顶/导带底移动。进行D掺杂后电子浓度也可进一步提高，这表明在贫氧化学生长条件下进行D掺杂有利于提高其光生载流子。这为我们提供了一种调节本征缺陷浓度的方法，并加深了我们对形成能与费米能级图的理解和应用的认识。
