Tolerance against conducting filament formation in nanosheet-derived titania thin films

Herein, titania thin films are fabricated by a facile liquid-phase method based on vacuum filtration of a colloidal suspension of titania nanosheets, which is followed by thermal annealing to transform the nanosheet film into anatase TiO2. Nanosheet-derived titania thin films exhibit poor resistive switching with an interface-type mechanism. This behaviour is distinct from the filamentary switching that has been observed with titania thin films fabricated by other conventional techniques. This tolerance against conducting-filament formation may be ascribed to a low concentration of oxygen vacancies in nanosheet-derived films, which is expected because of the O/Ti ratio of titania (Ti0.87O2) nanosheets being larger than that of TiO2. Besides, the dielectric breakdown strength of nanosheet-derived films is found to be comparable to or higher than that of titania thin films fabricated by other techniques. These findings clearly indicate the usefulness of nanosheet-derived titania thin films for dielectric applications.