Resistance switching in metal oxides could form the basis for next-generation non-volatile memory. It has been argued that the current in the high-conductivity state of several technologically relevant oxide materials flows through localized filaments, but these filaments have been characterized only indirectly, limiting our understanding of the switching mechanism. Here, we use high-resolution transmission electron microscopy to probe directly the nanofilaments in a Pt/TiO2/Pt system during resistive switching. In situ current-voltage and low-temperature (∼130 K) conductivity measurements confirm that switching occurs by the formation and disruption of Ti nO2n-1 (or so-called Magnéli phase) filaments. Knowledge of the composition, structure and dimensions of these filaments will provide a foundation for unravelling the full mechanism of resistance switching in oxide thin films, and help guide research into the stability and scalability of such films for applications.
Bibliographical noteFunding Information:
This work was supported by National Research Foundation of Korea grant funded by the Ministry of Education, Science and Technology (2009-0083038) and MEST-AFOSR NBIT Program. C.S.H., K.M.K., M.H.L. and K.H.K. acknowledge support by the National Program for 0.1 Terabit NVM Devices of the Korean Government, the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (grant no. 2009-0081961), and World Class University program through the Korea Science and Engineering Foundation funded by the Ministry of Education, Science and Technology (grant no. R31-2008-000-10075-0). B.L. and S.H. were supported by the Quantum Metamaterials Research Center (grant no. R11-2008-053-03001-0).
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Biomedical Engineering
- General Materials Science
- Condensed Matter Physics
- Electrical and Electronic Engineering