Electrical Switching in Thin Film Structures Based on Transition Metal Oxides

Abstract

Electrical switching, manifesting itself in the nonlinear current-voltage characteristics with S- and N-type NDR (negative differential resistance), is inherent in a variety of materials, in particular, transition metal oxides. Although this phenomenon has been known for a long time, recent suggestions to use oxide-based switching elements as neuristor synapses and relaxation-oscillation circuit components have resumed the interest in this area. In the present review, we describe the experimental facts and theoretical models, mainly on the basis of the Mott transition in vanadium dioxide as a model object, of the switching effect with special emphasis on the emerging applied potentialities for oxide electronics.

Modification of the Properties of Vanadium Oxide Thin Films by Plasma-Immersion Ion Implantation

“…The switching effect has been observed in vanadium dioxide single crystals and thin-film structures of both planar and sandwich-type [1,5,7], as well as in vanadate-phosphate glasses [26], VO 2 -containing ceramics [27], and V 2 O 5 -gel films [8,28]. When as-prepared samples do not consist of pure vanadium dioxide, preliminary electrical forming (EF) is required, resulting in formation of the VO 2 -containing channel [7,8,[26][27][28].…”

“…In addition, in MOM structures with vanadium dioxide, as well as in structures based on some other transition metal oxides, the phenomenon of electrical switching associated with MIT is observed [7]. The switching effect is a sharp, significant, and reversible change in the system conductivity under the action of the applied electric field.…”

“…The switching effect is a sharp, significant, and reversible change in the system conductivity under the action of the applied electric field. Doping VO 2 with various metals and hydrogen allows one to control the value of [1,[7][8][9][10] and, accordingly, the S-shaped I-V characteristic parameters, for example, the threshold voltage th . On the other hand, the study of the MIT in vanadium dioxide, doped with hydrogen or metals with a 2 Advances in Condensed Matter Physics valence greater than 4 (e.g., W 6+ ), is of great importance from the viewpoint of further understanding the transition mechanism.…”

“…Moreover, electrical switching is observed in MOM structures based on vanadium pentoxide gel films after electroforming which results in formation of a VO 2 channel inside the film between metal electrodes [7,8]. It has been shown that doping of the initial V 2 O 5 ⋅nH 2 O film with tungsten allows minimization of the statistical spread (which is an inevitable consequence of the electroforming process) of the th value [7,8].…”

“…It has been shown that doping of the initial V 2 O 5 ⋅nH 2 O film with tungsten allows minimization of the statistical spread (which is an inevitable consequence of the electroforming process) of the th value [7,8]. This minimization is surely important for practical applications of vanadium oxide switches [7].…”