Assessment and Modeling of NH3-SnO2 Interactions using Individual Nanowires

To date, studies on the interactions between ammonia and monocrystalline SnO2 surface have been scarcely explored in real conditions. On the contrary, thin and thick films are used to that end, despite their electrical signal is affected by intrinsic limitations that distort the response. Here, individual and well-faceted SnO2 nanowires were used as sensors in which the ammonia detection characteristics of this metal oxide were evaluated. After confronting experimental data with simulations, it was concluded that both lattice and pre-adsorbed oxygen species play a key role to complete the reaction pathway of ammonia onto SnO2, with N2 and H2O as resulting products. This explained the response and dynamics of such devices as function of ammonia concentration and temperature. Moreover, the blocking influence of humidity on the ammonia response was explored. These results provide new insights into the fundamentals of the NH3-SnO2 interactions.