【Device Papers】Performance improvement of ε-Ga₂O₃ solar-blind UV photodetector via an α-Ga₂O₃ buffer layer

      Researchers from the Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences have published a dissertation titled "Performance improvement of ε-Ga₂O₃ solar-blind UV photodetector via an α-Ga₂O₃ buffer layer" in Materials Science in Semiconductor Processing.

Abstract

      The heteroepitaxial growth of ε-Ga₂O₃ thin films has long been constrained by significant lattice and thermal mismatch with commonly used substrates, typically leading to moderate crystalline quality and high defect density. To address this limitation, we developed a strategy involving the introduction of an α-Ga₂O₃ buffer layer between the c-plane sapphire substrate and the ε-Ga₂O₃ film, achieving high-quality ε-Ga₂O₃ thin films via metal-organic chemical vapor deposition. This method utilizes multiple crystal phases within the same material system, alleviating lattice and thermal mismatch without introducing any foreign impurities. By introducing the α-Ga₂O₃ buffer layer, the full width at half maximum of the X-ray diffraction rocking curve of ε-Ga₂O₃ film decreased from 0.67° to 0.62°, accompanied by a 48% reduction in oxygen vacancy concentration. More notably, the ε-Ga₂O₃-based photodetector incorporating the buffer layer exhibited significantly suppressed dark current, markedly accelerated response speed. Typically, the spectral rejection ratio (R_{240 nm}/R_{350 nm}) was enhanced over two orders of magnitude, from 1.18 × 10³ to 1.55 × 10⁵. This study not only demonstrates that the α-Ga₂O₃ buffer layer is an effective method for achieving high-performance ε-Ga₂O₃-based optoelectronic devices, but also provides a viable strategy for addressing common challenges in material heteroepitaxy.

DOI：

https://doi.org/10.1016/j.mssp.2026.110616