Surface sensitization of metal oxide quasi-1D sensors: in situ comparative study of pristine and Pd doped individual SnO/sub 2/ nanostructure

We have developed the technique for in situ monitoring of the process of surface functionalization of the pre-selected 1-D nanostructure with catalytic particles of Pd. The method allows us to compare directly the sensing performance of the individual SnO2 nanobelt chemical sensor before and after surface sensitization. The conductance evolution at early stages of the metal deposition before percolation indicates that Pd nanoparticles formed on the nanowire surface induce regions depleted with electrons which narrow the effective conduction channel and therefore are responsible for the conductance drop. After being functionalized with Pd the nanostructure exhibited drastic improvement of the sensitivity toward oxygen and hydrogen due to enhanced activation of molecules on Pd nanoparticle surface and diffusion of resultant reactive species to the oxide surface