Role of oxygen vacancies and In-doping on the sensing performance of ZnO particles

Pure and In-doped ZnO particles with two morphologies: rods and platelets were synthesized using hydrothermal method and tested for gas sensing. The materials were characterized by X-ray diffraction, scanning electron microscopy and Raman spectroscopy. Platelets were synthesized with zinc acetate and potassium hydroxide in a ratio 1:3, while rods were obtained for a ratio1:8. As-synthesized particles do not exhibit any sensing response. The creation of oxygen vacancies, through thermal treatments under reducing atmosphere (Ar:H2), activate the sensing properties. The best sensitivity, upon exposure of CO and propane, was obtained on the In-doped platelets with large ±(0001) surface area. The value of the contact barrier between particles after the thermal treatment is 164 µeV. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)