SnO2:F/β-Ga2O3 thin-film heterojunctions as sensitive photodetectors for short-wavelength UV radiation

• FTO/β-Ga 2 O 3 photodetectors were fabricated via spray pyrolysis and optimized at 0.2 M Ga 2 O 3 . • Films showed band gaps of 4.59 eV (β-Ga 2 O 3 ) and 3.38 eV (FTO), with superior FTO crystallinity. • The optimized device achieved 47.72 mA/W responsivity and 3.34 × 10 8 Jones detectivity for UVC monitoring. Monitoring UVC radiation from the ozone hole is crucial due to its harmful effects on both the environment and human health. To address this need, photodetectors operating in the short-wavelength ultraviolet (UVC) region are essential. In this study, optical photodetectors based on thin films of fluorine-doped tin oxide (SnO 2 :F or FTO) and gallium oxide (β-Ga 2 O 3 ) were fabricated using the spray pyrolysis technique. Initially, individual thin films of SnO 2 :F and β-Ga 2 O 3 were prepared and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis spectroscopy, and current–voltage (I–V) measurements. Subsequently, photodetectors composed of stacked SnO 2 :F/β-Ga 2 O 3 thin films were fabricated, and their photoresponse was evaluated by varying the concentration of Ga 2 O 3 . Among the tested concentrations, the device with 0.2 M Ga 2 O 3 exhibited the best performance, with a sensitivity of 6.62 × 10 −2 , an external quantum efficiency (EQE) of 233.92 %, and a responsivity of 47.72 mA/W. These results suggest that SnO 2 :F/β-Ga 2 O 3 thin-film photodetectors are promising candidates for UVC detection and can be effectively utilized in environmental monitoring applications, such as ozone hole observation.