Abstract
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.
Highlights
Metal oxides are used in modern electronics as a high-κ dielectric for miniaturized transistors [1,2,3] and as a switching medium for resistance change memories [4,5,6] including memristors [7,8,9]
We investigated the resistive switching behaviour and dielectric strength of titania thin films, which were fabricated by a facile liquid-phase method based on the vacuum filtration of a colloidal suspension of titania nanosheets
The nanosheet-derived thin films after annealing were confirmed to correspond to the anatase phase of TiO2. They exhibited a poor resistive-switching behaviour with the interface-type mechanism, which was distinct from the filamentary mechanism observed in titania thin films fabricated by other conventional techniques
Summary
Metal oxides are used in modern electronics as a high-κ dielectric for miniaturized transistors [1,2,3] and as a switching medium for resistance change memories [4,5,6] including memristors [7,8,9]. Vacuum filtration of a colloidal suspension of titania nanosheets is employed as a facile liquid-phase method for the fabrication of titania thin films. Vacuum filtration methods have been widely applied for the thin film formation of various nanosheets ranging from chalcogenides [19] to oxides [20]. The nanosheet-derived thin films with photolithographically patterned Au electrodes exhibit resistive switching, which can be explained using the framework of the interface-type mechanism. In Au-contacted titania thin films fabricated by other methods, the switching is interpreted using the filamentary mechanism. This tolerance of the nanosheet-derived titania thin films to the formation of conducting filaments may be attributed to the difference in the. The present finding indicates the suitability of nanosheetderived titania films for dielectric applications
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