Features of contact and surface processes in glassy As2Te13Ge8S3-based structures with Pt electrodes upon interaction with nitrogen dioxide

Abstract

The capacitance spectra of the interdigital Pt-glassy As2Te13Ge8S3-Pt structures have been investigated in a range of 5-106 Hz with respect to temperature effects in both dry air and its mixture with a controlled concentration of nitrogen dioxide. It has been found that a decrease in the frequency of applied voltage to 103 Hz results in a rapid increase in the capacitance by several orders of magnitude. Environmental conditions dramatically influence the capacitance at low frequencies and, together with temperature regime, control the capacitance spectra and current-voltage characteristics of the films. The results are explained in terms of formation of a Schottky-Mott barrier that controls the properties of the contact junction. The contact-free part of the chalcogenide film surface, being more conducting than the bulk, acts as a capacitor, which can be controlled by interaction with gaseous species from the environment.