Formation of energy barrier by adsorbed on ZnO
Abstract The energy barrier on the surface of porous ZnO was formed by the chemisorbed oxygen. The height of such a barrier and the resultant change in the electrical conductivity depended on the amount and oxidation state of the adsorbed oxygen. The formed barrier was examined by measuring both current-voltage and capacitance-voltage characteristics. The barrier height decreased rapidly at room temperature, which was attributed to the change in the oxidation state of the chemisorbed oxygen. The addition of cobalt oxide stabilized the oxidation state of chemisorbed oxygen and increased the barrier height.