Fabrication and characterisation of Ga₂O₃and GaO(OH) particles synthesised by forced hydrolysis

GaO(OH) particles were synthesised using a low-cost forced hydrolysis method, and their thermal conversion into Ga₂O₃was investigated as a function of annealing temperature and initial solution pH. Raman spectroscopy revealed the formation ofα-GaO(OH) for anneals between room temperature and 300 °C, with optimal crystal quality observed at 200 °C-300 °C. Subsequently,α-Ga₂O₃was produced between 300 °C and 600 °C, peaking in quality at 500 °C, andβ-Ga₂O₃was obtained between 600 °C and 900 °C, with the highest quality achieved at 900 °C. Temperature-dependent photoluminescence revealed phase-dependent emission and thermal quenching associated with defect-related recombination. A proof-of-concept ultraviolet (UV) photodetector fabricated fromβ-Ga₂O₃particles exhibited a responsivity of 78.7 ± 0.8μA W^-1at 250 nm, a photo-to-dark current ratio of 815, and a 250 nm/375 nm rejection ratio of 72. These results underscore the potential of this low-cost synthesis route for UV detection and UV-assisted gas sensing applications.