Density Functional Theory Study of ZnO Nanostructures for NO and NO2 Sensing

Using both experimental and theoretical techniques we examine ZnO nanostructures for gas sensing of NO₂ and NO. ZnO nanoparticles were synthesized using liquid phase techniques. Density functional theory calculations of NO₂ and NO adsorbed on the (101macr0) surface of ZnO showed that the interaction between the adsorbate and surface is very weak. The structure of the surface, as well as NO₂ and NO are changed little upon adsorption. A positive work function change is caused by both adsorbates, indicating there is a transfer of charge from the surface to the adsorbate. Such a change is consistent with the experimental observation that NO₂ reduces the conductivity of the substrate.