Humidity sensor based on synthesized pure WO₃ and WO₃-SnO₂ nanocomposite

Abstract

In this paper we report humidity sensing studies of undoped and SnO 2 doped WO 3 . Sensitivity is 13.48 MΩ/%RH for WO 3 -SnO 2 nanocomposite. Hysteresis is less than 3% for WO 3 -SnO 2 nanocomposite. Aging for WO 3 -SnO 2 nanocomposite is 5.7%. Activation energy for conduction obtained from Arrhenius graph are 0.127 eV in 27°C to 200°C and 0.547 eV in 200°C to 600°C temperature range . Response time and recovery time for sample WO 3 -SnO 2 nanocomposite are 117 s and 411 s respectively, while that for sample WO 3 are 172 s and 557 s respectively. Average grain size calculated from SEM micrographs for WO 3 and WO 3 -SnO 2 nanocomposite are 135 nm and 150 nm respectively.