A decade of gallium oxide thin film research: a bibliometric and co-citation network analysis

The ultrawide bandgap (UWBG) semiconductor gallium oxide (Ga₂O₃) has rapidly emerged as a transformative material in electronic and optoelectronic applications due to its exceptional properties—high breakdown electric field, chemical stability, and compatibility with low-cost, large-area substrates. Among its polymorphs, β-Ga₂O₃ has become the focal point of intense global research, particularly in the context of thin film technologies for power devices, solar-blind ultraviolet (UV) photodetectors, and high-temperature sensors. Despite this growing interest, a comprehensive, data-driven assessment of the knowledge structure and research evolution within this domain has, to our knowledge, not been previously attempted in this depth specifically for Ga₂O₃ thin-film research. This study presents an in-depth bibliometric and co-citation network analysis of Ga₂O₃ thin film research from 2015 to 2025. The dataset of 945 articles was retrieved from the Web of Science Core Collection on June 27, 2025, using the keywords ‘thin film’ AND (‘Ga₂O₃’ OR ‘Gallium Oxide’), limited to English-language journal articles indexed in SCI-EXPANDED from 2015 to 2025. Our findings highlight a steady rise in publications and citations, peaking in 2024, with significant intellectual contributions by researchers such as Stephen Pearton, Masataka Higashiwaki, and Daoyou Guo. The document co-citation analysis identifies foundational works that have shaped key research directions, including β-Ga₂O₃ device architectures, defect engineering, and thin film fabrication methods. Cluster analysis reveals distinct thematic groupings such as solar-blind photodetectors, amorphous Ga₂O₃ devices, high-temperature sensing, and band structure engineering. Keywords like “oxide semiconductor” “temperature sensors,” and “ion implantation,” show strong recent citation bursts, indicating emerging trends in high-performance and application-specific device integration. The study also uncovers dominant global contributors—led by China, the USA, Japan, South Korea, and India—and emphasizes the roles of high-impact journals such as Applied Physics Letters, ACS Applied Materials & Interfaces, and Journal of Alloys and Compounds. The country/region, institutional, and author collaboration networks illustrate the growing interconnectedness of the field and the formation of strong research ecosystems. Overall, this paper offers a quantitative analysis of the last decade of Ga₂O₃ thin film research and provides a strategic lens to identify influential contributions, research gaps, and future opportunities. It serves as a valuable resource for scientists, engineers, and funding agencies aiming to navigate and contribute to the rapidly evolving landscape of Ga₂O₃-based semiconductor technologies.