The study of high-dc electric field effect on the conduction of V₂O₅–Sb–TeO₂ glasses and the applicability of an electrothermal model

Ternary (60−x)V₂O₅–xSb–40TeO₂ oxide glasses (with 0 ≤ x ≤15 in mol%), prepared using the usual melt quenching method, were investigated electrically (at the presence of high-dc electric fields) within the temperature range of 298–375.3 K at different electrode distances. The current–voltage characteristics show increasing deviations from Ohm’s law at electric fields of about >10³ V/cm. This behavior can be attributed to the Pool–Frenkel effect, which usually occurs at the mentioned electric fields. At higher fields, switching (from low conduction state to higher conduction state) or negative resistance phenomena were observed at a threshold voltage (V _th). The threshold voltage for beginning the switching/negative resistance shows a decreasing trend with increasing in temperature and also with decreasing of electrode distance. An electrothermal model (based on the Joule heating effect in the current filament) is proposed to interpret the observed electrical properties. Also, the lowering factor of potential barrier (β _PF) in Pool–Frenkel effect, heat dissipation factor, and electrical activation energy of the present samples were determined. In each sample, the increase of β _PF with temperature can explain the phonon-assisted hopping conduction.