【Others Papers】Defects-induced structural and optoelectronic properties in Se-implanted β-Ga₂O₃

      Researchers from the The Hong Kong University of Science and Technology （Guangzhou） have published a dissertation titled " Defects-induced structural and optoelectronic properties in Se-implanted β-Ga₂O₃" in Journal of Alloys and Compounds.

Abstract

      In this study, selenium ion implantation techniques were employed to achieve gradient Se doping in β-Ga₂O₃ single crystals, systematically investigating the optical and electrical properties of unintentionally doped and Se-implanted β-Ga₂O₃. Specifically, Se implantation was conducted at doses of 5 × 10¹⁴, 1 × 10¹⁵, 5 × 10¹⁵, 1 × 10¹⁶, and 5 × 10¹⁶ ions/cm², with an implantation voltage of 50 kV. First, defect calculations identified the transition energy levels of Se impurities, revealing that Se can act as a shallow donor level. Subsequent characterization using valence band X-ray photoelectron spectroscopy showed a shift in the Fermi level with increasing Se implantation dose, indicating potential p-type conductivity. Valence band X-ray photoelectron spectroscopy analysis demonstrated a gradual shift of the Fermi level toward the valence band as the implantation dose increased, confirming these defect-level transitions. Photoluminescence and photoluminescence excitation spectra showed an increase in blue luminescence due to donor-acceptor pair transitions, attributed to Se substitution at Ga sites. Atomic force microscopy and Raman spectroscopy indicated increasing surface roughness and lattice distortion with higher implantation doses, which likely resulted in the degradation of the material’s electrical and optical properties. This comprehensive investigation offers insights into the behavior of Se-implanted β-Ga₂O₃, which could advance the development of power devices and optoelectronic sensors.

DOI：

https://doi.org/10.1016/j.jallcom.2025.181122