4.3.2 Assessment and modeling of NH3SnO2 interactions using individual nanowire sensors

In this work, DFT (density functional theory) calculations were applied to study the interaction between NH3 and the SnO2 surface. To that end, two types of scenarios were selected; (i) the clean stoichiometric SnO2 (110) surface and (ii) a SnO2 (110) surface with pre-adsorbed Oads. The NH3 adsorption mechanism and charge transfer to the metal oxide after the adsorption and dissociation steps of the molecule were simulated to gain a deeper insight into the NH3 sensing mechanism of this metal oxide. Making use of the intrinsic advantages of nanoscale prototypes, the analysis of the nanowires’ resistance modulation upon exposure to NH3 and their dynamic response, as function of temperature and gas concentration, allowed validating some of the theoretical results.