Impacts of Point Defects on Shallow Doping in Cubic Boron Arsenide—A First Principles Study

Cubic boron arsenide (BAs) stands out as a promising material for advanced electronics, thanks to its exceptional thermal conductivity and ambipolar mobility. However, effective control of p- and n-type doping in BAs poses a significant challenge, mostly as a result of the influence of defects. E.g., the p-type behavior in pure BAs samples is claimed to be produced by impurity, rather than intrinsic defects, from previous computational studies. Here we employed density functional theory to explore the impacts of the common point defects and impurities on p-type (Be_B and Si_As) and n-type doping (Si_B and Se_As). We identified the most favorable point defects formed by C, O, and Si, including C_As, O_BO_As, Si_As, C_AsSi_B, and O_BSi_As, which all have formation energies of less than 1.5 eV. Based on these point defects, for p-type, only the O impurity detrimentally affects Si_As doping. However for n-type dopings, C, O, and Si impurities are all harmful. Interestingly, the antisite defect pair As_BB_As benefits both p- and n-type doping. While it is clear that n-type doping of BAs requires more caution in removing impurities, the doping limitation analysis presented in this study can potentially pave the way for strategic development in the area of BAs-based electronics.