On the Conduction Mechanism of Silicate Glass Doped by Oxide Compounds of Ruthenium (Thick Film Resistors). 3. The Minimum of Temperature Dependence of Resistivity

Abstract

This article is the final part of the investigation of conduction mechanism of silicate glass doped by oxide compounds of ruthenium (thick film resistors). In the first part [1], the formation of percolation levels due to diffusion of dopant atoms into the glass has been considered. The diffusion mechanism allowed us to explain shifting of the percolation threshold towards to lower value and the effect of firing conditions as well as the components composition on the electrical conduction of the doped glass. The coexistence of thermal activation and localization of free charge carriers as the result of nanocrystalline structure of the glass was the subject of the second part [2]. Because of it, the resistivity of the doped silicate glass is proportional to exp (-aT -ζ ) at low temperatures (T < 50 K), 0.4 < ζ < 0.8. Structural transitions of nanocrystals take place at high temperatures (T > 800 K) and the conductivity of the doped silicate glass decreases sharply. We consider the origin of the minimum in the temperature dependence of resistivity of the doped silicate glass here. It is shown that the minimum arises from merge of impurity band into the valence band of glass at temperature high enough, so thermal activation of charge carriers as well as its hopping are failed, and scattering of free charge carriers become predominant factor in the temperature dependence of the resistivity.

Impurity Bands and Density of State in Doped Silicate Glasses with Metal Oxides (RuO2, CuO, MnO2)

“…To determine the density of states g(E) according to formula (1), first of all, the effective mass of charge carriers m* should be determined [6][7][8].…”

“…Ruthenium oxide with doped silicate glass (DSG) is widely used in electronics and instrumentation as a "thick film resistor" [1] and is expected to be an effective thermoelectric material [2]. DSG can be considered a unique material that differs dramatically from metals and semiconductors due to the temperature dependence of electrical conductivity (Fig.…”

Псевдощель, Нанокристаллы И Электропроводность Легированного Силикатного Стекла

“…ЛСС является уникальным электронно-проводящим материалом [5][6][7][8][9][10][11][12][13][14][15][16], в котором при изменении температуры от гелиевых до 1200 K последовательно реализуются несколько режимов электропроводности (рис. 3).…”

“…Сочетание нанокристаллов и примесной зоны с электрон-фононной связью (влияющей на положение примесной зоны [25][26][27][28][29]) дало объяснение минимуму ρ(T ) и последующей за ним в низкоомных ЛСС " металлической" проводимости ρ ∝ T α , α = 1−2 [5]. Было установлено [5,18], что последняя является следствием слияния примесной зоны с валентной зоной стекла, когда основной причиной температурной зависимости проводимости ЛСС становится рассеяние носителей на ионах, фононах и друг на друге.…”

“…1-3стекла разных составов. Во врезке низкотемпературная часть показана в увеличенном масштабе[5,18].…”