Fabrication and characterisation of Ga2O3 and GaO(OH) particles synthesised by forced hydrolysis.

Gallium oxide (Ga2O3) nanoparticles were synthesised via forced hydrolysis, employing a range of annealing temperatures from room temperature (24 °C) to 900 °C for pH starting conditions 7.5 and 9.5. The crystal phase was controlled using annealing treatment, and monitored using Raman spectroscopy, and the optical bandgap and luminescence were systematically investigated using UV‑vis spectrophotometry and cathodoluminescence. GaO(OH) formed between room temperature (24 °C) and 300 °C, with optimal crystal quality observed at 200-300 °C. Meanwhile α‑Ga2O3 emerged between 300 °C and 600 °C, peaking in quality at 500 °C, and β‑Ga2O3 was produced between 600 °C and 900 °C, with the highest quality achieved at 900 °C. A proof‑of‑concept UV photodetector demonstrated a responsivity of 72.1 μA/W at 250 nm, a photo‑to‑dark current ratio of 122, and a 250 nm/375 nm rejection ratio of 67. These results underscore the potential of this low‑cost synthesis route for UV detection and UV‑assisted gas sensing applications.