Resistance switching and retention properties of Pt/TiO2 Schottky junction devices are improved by doping anatase TiO2 thin films with Co ions. Co-doped TiO2 devices exhibit excellent rectifying current-voltage characteristics and resistance switching compared to undoped TiO2 devices. Conventional Schottky junction devices such as Pt/Nb:SrTiO3 and Pt/TiO2 devices exhibit very poor resistance retention properties in low resistance state (LRS); the resistance in LRS increases with time and the resistance relaxation accelerates with an increase in temperature. Co-doped TiO2 devices show excellent resistance retention properties even at 100 degrees C. Experimental results indicate that in Schottky junction devices, resistance switching originates from the formation of local tunneling paths, and the oxygen vacancies near the electrode interface play an important role in resistance switching. These results are very important from the point of view of understanding the resistance switching mechanism and improving the resistance switching properties of Schottky junction devices. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3529247] All rights reserved.