【Device Papers】Toward Low-Dark-Current Solar-Blind UV Photodetectors: Ozone-RTA Suppression of Oxygen Vacancies in Ni-Doped β-Ga₂O₃

      Researchers from the Jimei University have published a dissertation titled " Toward Low-Dark-Current Solar-Blind UV Photodetectors: Ozone-RTA Suppression of Oxygen Vacancies in Ni-Doped β-Ga₂O₃" in Vacuum.

Abstract

      In this work, Ni-doped Ga₂O₃ films deposited on sapphire substrates by radio-frequency magnetron sputtering were treated by rapid thermal annealing in an ozone atmosphere for 30 s. The effects of annealing temperatures ranging from 600 to 900 °C on the structural, chemical, and optoelectronic properties of films were investigated. X-ray diffraction confirmed the presence of β-Ga₂O₃ crystalline phases (−402) and (−603) at higher temperatures than 800 °C. X-ray photoelectron spectroscopy verified that reactive oxygen generated from ozone decomposition effectively passivated oxygen vacancies, achieving a lattice oxygen concentration of 91.02%. The influence of Ni²⁺ doping on the film properties was analyzed. Through defect engineering and band structure optimization, a potential strategy to realize p-type Ga₂O₃ is proposed. Based on this, a solar-blind ultraviolet photodetector was fabricated under the optimal condition of 800 °C, showing an ultra-low dark current of 0.13 pA and a dramatic increase of photocurrent-to-dark current ratio (I_photo/I_dark) from as-deposited 8 to 1184.62. It is found that optimization of the doping process can further enhance the hole concentration and mobility, aiming to meet the industrial requirements of various applications.

DOI：

https://doi.org/10.1016/j.vacuum.2026.115383