$\beta \hbox {-}{\rm Ga}_{2}{\rm O}_{3}$ Nanowires-Based Humidity Sensors Prepared on GaN/Sapphire Substrate

We report the growth of β-Ga₂O₃ nanowires (NWs) on GaN substrate and the fabrication of β-Ga₂O₃ NW humidity sensors. It was found that average length and diameter were ~10 μm and 100 nm, respectively. It was also found that the current of the NWs increased as we increased the relative humidity because of the n-type nature of β-Ga₂O₃. Through measuring current-voltage characteristics of the fabricated device at 25 °C, it was found that the measured currents were 5.99×10^-5, 6.42×10^-5, 6.76×10^-5, 7.33×10^-5, and 7.93×10^-5 A when measured with 35%, 50%, 65%, 85%, and 95%-relative humidity, respectively.