【Others Papers】Temperature-driven lattice transformation in Al-doped β-Ga₂O₃ nanostructures and its application in VOC detection

      Researchers from the Indian Institute of Technology Kharagpur have published a dissertation titled "Temperature-driven lattice transformation in Al-doped β-Ga₂O₃ nanostructures and its application in VOC detection" in Journal of Alloys and Compounds.

Abstract

      This work presents a systematic investigation of Al-doped β-Ga₂O₃ nanostructures for selective formaldehyde (HCHO) detection, emphasizing comparative VOC benchmarking and kinetics-based analysis. The materials, synthesized via a low-cost hydrothermal–precipitation route, exhibit controlled lattice contraction with increasing Al content (0–10 wt%), as confirmed by Rietveld refinement. The induced compressive lattice strain enhances oxygen vacancy formation and modifies the electronic structure, as evidenced by XPS and UPS analyses, thereby promoting adsorption of oxygen species and improving charge transfer during gas interaction. Temperature-dependent lattice studies, well described by the Einstein model, reveal thermally driven lattice expansion while maintaining structural stability up to 300 °C, ensuring reliable sensing performance under operating conditions. Importantly, a direct correlation between lattice strain (∼0.22–0.36%) and sensing response is observed, where optimized strain maximizes adsorption sites and charge transfer efficiency. The optimized 5 wt% Al-doped β-Ga₂O₃ sensor shows superior selectivity toward formaldehyde compared to other VOCs under identical conditions, achieving a low detection limit of 7.70 ppb. Kinetic analysis based on the Eley–Rideal model yields a low activation energy of 0.2353 eV, confirming a surface-controlled sensing mechanism. The enhanced sensing performance is therefore attributed to lattice-induced defect engineering, which optimizes adsorption and charge transfer pathways, enabling highly selective and sensitive formaldehyde detection.

DOI：

https://doi.org/10.1016/j.jallcom.2026.188071