Site-selectively grown SnO₂ NWs networks on micromembranes for efficient ammonia sensing in humid conditions

Abstract

SnO₂NWs networks on heated micromembranes have been characterized as ammonia sensors. Theapproach allows achieving reproducible growth and stable and long-lasting ammonia sensors with site-specific grown SnO₂NWs. The devices have been tested both in dry and humid conditions showingresponse time down to two minutes. Sensors have been tested up to 1 month, only presenting variationof the base resistance with full retention of the response towards the gaseous analytes. Different concur-rent sensing mechanisms have been identified relating the determined sensing kinetics with previoustheoretical calculations. Specifically, oxygen dissociation seems to play a key role in the overall ammoniasensing sequence. In humid conditions, moisture reduces the response to ammonia but also lowers theactivation energy of the reaction process.