Point defects and dopants of boron arsenide from first-principles calculations: donor compensation and doping asymmetry*

BAs has received attention due to its unusually high thermal conductivity, yet, its defect properties are relatively unknown. Particularly, point defects crucially affect its electronic, thermal, and optical properties as a semiconductor. Here, we apply hybrid density functional theory calculations to identify the formation energies and thermodynamic charge transition levels of native point defects, common impurities, and shallow dopants in BAs [1]. We find that As_B, V_B, B_As, B_i-V_B, As_B-B_As, are the dominant intrinsic defects, while C_As, C_B, H_i are common impurities. Be_B, Si_As and Ge_As are predicted to be excellent shallow acceptors with low ionization energy (< 0.03 eV) and negligible compensation by other point defects. However, donors such as Se_As, Te_As, Si_B, and Ge_B have a relatively large ionization energy (~0.15 eV) and are likely to be passivated by native defects such as B_As and V_B, as well as C_As, H_i, and H_B. The hole and electron doping asymmetry originates from the heavy effective mass of the conduction band due to its boron orbital character, as well as from boron-related intrinsic defects that compensate donors.
[1] arXiv:1809.09213