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Oxygen Vacancy Creation, Drift, and Aggregation in TiO 2 ‐Based Resistive Switches at Low Temperature and Voltage
Author(s) -
Kwon Jonghan,
Sharma Abhishek A.,
Bain James A.,
Picard Yoosuf N.,
Skowronski Marek
Publication year - 2015
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201500444
Subject(s) - materials science , oxygen , vacancy defect , rutile , dissociation (chemistry) , tin , electric field , coalescence (physics) , transmission electron microscopy , condensed matter physics , chemical physics , crystallography , nanotechnology , chemical engineering , chemistry , metallurgy , physics , organic chemistry , quantum mechanics , astrobiology , engineering
Transmission electron microscopy with in situ biasing has been performed on TiN/single‐crystal rutile TiO 2 /Pt resistive switching structures. Three elementary processes essential for switching: i) creation of oxygen vacancies by electrochemical reactions at low temperatures (<150 °C), ii) their drift in the electric field, and iii) their coalescence into planar faults (and dissociation from them) have been documented. The faults have a form of vacancy discs in {110} and {121} planes, are bound by partial dislocation loops, and are identical to Wadsley defects observed in nonstoichiometric TiO 2 annealed at high temperatures. The faults can be regarded as a precursor to the formation of oxygen‐deficient Magnéli phases, but 3D secondary phase inclusions have not been detected. Together, the observations shed light on the behavior of oxygen vacancies in relatively low electric fields and temperatures, suggesting that, in addition to the rather accepted notion of oxygen vacancy motion during the writing processes in resistive switching devices, such motion may occur even during reading, and may be accompanied by significant oxygen vacancy creation at modest device excitation levels.