Temperature effects on self-organized patterns and characteristics of bistable ZnS:Mn thin-film structures

A temperature (T) rise from 20 up to 80 °C results in some decrease of the threshold voltage and slope of the voltage (V) dependences of the luminance and the transferred charge of the electron-beam evaporated ZnS:Mn ac thin film electroluminescent structures (ac TFELS) showing different patterns or no patterns in the emission. Such a heating leads to an improvement of the dynamics of all the patterns, to a narrowing and acceleration of the autowave (AW) front. However, the dynamic patterns are not formed by such a heat treatment if they are absent at any frequency of V and T = 20 °C. Although AWs more often take place at 70-80 °C, they have also been observed at T < 40 °C in some samples. It has been concluded that heating is not a sufficient condition for the formation of patterns. It enhances the generation of initial free electrons at a given V, promotes a lateral spreading of the non-equilibrium charge carriers, but decreases the rate of all processes responsible for the bistability of the TFELS and the self-organization in them.