Effects of reaction pH on regular nanorods and hierarchically structured β-Ga₂O₃ and their isopropanol sensing capabilities

Real-time detection of isopropanol is important for indoor air quality monitoring to improve human health. In this study, regular and hierarchical nanorod-based β−Ga₂O₃ morphological features were prepared using the microwave-assisted hydrothermal method following the variation of the reaction pH levels. A systematic study on their gas sensing performances was conducted to evaluate their potential as isopropanol gas sensing platforms. The sensor response and response times were directly controlled by morphology of β−Ga₂O₃. The randomly oriented β−Ga₂O₃ nanorods presented the highest response of 6.7 towards 90 ppm isopropanol while the β−Ga₂O₃ nanodandelions showed the fastest response/recovery times of 47/25 s. The observed variation in the gas sensing performances of the different β−Ga₂O₃ structures can be attributed to changes in morphological, textural, and compositional properties induced by the controlled reaction pH levels.