【Epitaxy Papers】Low temperature self-buffered growth of high quality β-Ga₂O₃ thin films

      Researchers from the Shandong University have published a dissertation titled "Low temperature self-buffered growth of high quality β-Ga₂O₃ thin films" in Applied Surface Science.

Abstract

      Beta-gallium oxide (β-Ga₂O₃), an ultra-wide bandgap semiconductor, emerges as a compelling candidate for next-generation high-voltage electronics and deep-UV optoelectronics. However, conventional epitaxy often demands high thermal budgets to overcome interfacial strain and chemical potential barriers, which triggers detrimental impurity diffusion and secondary phase formation, ultimately constraining device-level integration. This study proposes a self-buffered interfacial engineering strategy, in which Zr⁴⁺ ions with strong oxygen affinity spontaneously form Zr-enriched self-buffering layers at β-Ga₂O₃/AZO interfaces through interfacial enrichment effects. The graded transition structure within self-buffering layer substantially alleviates the original ∼ 3.6% lattice mismatch between β-Ga₂O₃ and AZO, simultaneously reducing strain-induced defects at the β-Ga₂O₃/AZO interface. First-principles calculations demonstrate the interfacial stabilization capability of Zr⁴⁺, with its oxygen adsorption energy (−20.19 eV/atom) doubling that of Ga³⁺ (−10.49 eV/atom), driving spontaneous interfacial accumulation. These insights collectively explain and support the feasibility of localized coherent growth of β-Ga₂O₃ on AZO substrates without intentional heating. Additionally, the improved crystalline quality of β-Ga₂O₃ is also evidenced by the high rectification ratio (3 × 10⁴) and low ideality factor (1.6) of optimized Cu₂O (2000 nm)/β-Ga₂O₃:1%Zr (30 nm)/AZO (500 nm)/glass heterojunction device. This work not only provides theoretical guidance for wide bandgap semiconductor low-temperature heteroepitaxy, but also establishes a universal strategy for next-generation advanced power chips and flexible optoelectronic systems.

DOI：

https://doi.org/10.1016/j.apsusc.2026.167823