Enhancement of the switchable diode effect by the surface hydroxylation of ferroelectric oxide thin films

The diode behavior of ferroelectric materials was shown to be enhanced using aqueous solution treatment of their surface. The electric current increased for both BaTiO3 and BiFeO3 nano-films after being treated with aqueous solution as compared with their as-grown films. The hydroxyl groups were confirmed to be successfully bonded on the surface, which increased the concentration of oxygen vacancies near the film surface. The rectifying diode effect can be associated with the polarization direction and the movement and redistribution of oxygen vacancies within the ferroelectric thin films. Further the enhanced diode effect for the hydroxylated film was attributed to the increased oxygen vacancies near the top electrode/film interface. The reported finding helps us understand the role of water as the most common polar molecule in the atmosphere on the ferroelectric materials that exist in many industrial devices. This will provide a low-cost strategy for improving the performance of resistive memory.