The Synergistic Effect of Bi Alloying and N, P Doping on p‐Type Conductivity and Optical Property of β‐Ga ₂ O ₃

Abstract The synergistic effects of Bi alloying and N/P doping on the p‐type conductivity and optical property of β‐Ga 2 O 3 are studied using density functional theory (DFT). Bi alloying elevates the valence band maximum of β‐Ga 2 O 3 through interactions between Bi and the host valence band, significantly enhancing the mobility of both electrons and holes. Subsequently, N and P dopants are introduced at two distinct three‐coordinated oxygen sites in the (Bi 1/8 Ga 7/8 ) 2 O 3 . The calculated acceptor levels for N1‐ and N2‐doped systems are 0.46 and 0.26 eV, respectively, while those of P1 and P2 doping are 0.9 and 0.57 eV. The shallower acceptor levels in N‐doped systems indicate that they are more conducive to achieving p‐type conductivity compared to P‐doped configurations. Moreover, both N and P doping extend the optical absorption of (Bi 1/8 Ga 7/8 ) 2 O 3 into the visible light region, markedly improving visible‐light utilization within the 200–600 nm range. Among all configurations, P substitution at the three‐coordinated O1 site yields the strongest visible‐light absorption, which remains optimal even at wavelengths beyond 600 nm.