Comparison in Absorption Current Characteristics between an Electronic-Conducting and an Alkali-Containing Glass

Abstract

The time and temperature dependences of the absorption current in an electronic-conducting glass (5Fe2O3⋅35BaO⋅60SiO2) and a plate glass were investigated using vacuum evaporated Au electrodes.The curves in log (absorption current) vs. log (time) diagrams for both glasses seemed to be the sum of two kinds of decreasing current. Part A was observed at the initial stage and decreased rapidly. On the other hand, Part B decreased slowly. Part A was masked by Part B at high temperature. The absorption current designated as Part A was converted to e′ by Hamon's approximation formula. The value of experimental activation evergy and the lack of voltage dependence suggested that Part A was caused by dielectric absorption in bulk glass.Part B vanished when the electronic-conducting glass was heated at 350°C for 4 hours in vacuum before the deposition of Al-Au electrodes. This suggested that Part B of this glass was caused by space charge polarization at electrode-glass interface and that adsorbed or absorbed water on glass surfaces was responsible for the polarization.For the case of plate glass, Part B could not be removed by prior heat-treatment at high temperature in vacuum. Part B of the plate glass seemed to be the result of space charge polarization caused by the displacement of alkali-ions.