SnO2 nanostructured thin film as humidity sensor and its application in breath monitoring

Abstract

In the present paper, we studied SnO2 nanostructured thin film-based resistive type humidity sensor fabricated by spin coating method on alumina substrate and showed its application in real time respiratory monitoring. Experiments show the growth of crystalline SnO2 nanoparticles with a tetragonal phase, with an average particle size of ∼15 nm and a high surface roughness of the order of 50-60 nm. The gold-interdigitated electrodes were patterned on the SnO2 film surface by DC sputtering technique to study the sensing response of the film. The sensor shows a high sensitivity of 1.34 kΩ/%RH, a minimal hysteresis of 0.94%, and good repeatability. The developed sensor is tested for monitoring human breath patterns in different physical conditions, and apnea like situations, which suggests its potential for clinical applications. Overall, the present work proposes an environmental friendly, easy-to-synthesize, highly stable, and simple facile SnO2 based deployable humidity sensor to diagnose human health patterns in a non-contact manner.