【Substrate Papers】Unveiling Bi doping effect in β-Ga₂O₃: lattice engineering, band hybridization, and ultraviolet photoresponse tailoring

      Researchers from the Sichuan Normal University of Sichuan Province have published a dissertation titled "Unveiling Bi doping effect in β-Ga₂O₃: lattice engineering, band hybridization, and ultraviolet photoresponse tailoring" in Journal of Alloys and Compounds.

Abstract

      β-Ga₂O₃ presents unique optoelectronic characteristics, making it a favorable material platform for constructing promising high-power electronics and ultraviolet photonic devices. In this work, we demonstrate bismuth (Bi) doping as a heavy metal element doping strategy to engineer the band structure and defect landscape of β-Ga₂O₃. Bi implantation induces lattice expansion and tensile strain, leading to a gradual redshift in the absorption edge with increasing doping concentration. First-principles calculations reveal that the substitutional Bi on octahedral Ga site results in the lattice expanding and the band structure modification. Critically, the hybrid coupling of O-2p and Bi-6s orbitals creates an intermediate band (IB) with shallow acceptor states. This unique band configuration enables sub-bandgap photon harvesting, leading to enhancement in ultraviolet photoresponse in β-Ga₂O₃:Bi. This work shows Bi doping effects in modifying lattice defects and band hybridization of β-Ga₂O₃, establishing IB engineering as a paradigm for advancing high-performance β-Ga₂O₃-based ultraviolet optoelectronics and towards p-type doping in wide-bandgap semiconductors.

DOI：

https://doi.org/10.1016/j.jallcom.2025.183932