Current fluctuations in negistor structures based on noncrystalline Ga-Te films

Abstract

The results of investigation of low-frequency (up to 10⁶ Hz) and microwave (at a frequency of 10 GHz) electric current fluctuations in negistor structures of the type of glass carbon-noncrystalline Ga_{1 − x} Te _x film (where x = 0.75 or 0.80)-glass carbon are presented. Low-frequency current fluctuations are studied in strong electric fields up to the emergence of electric instability, while microwave fluctuations are studied after the current pinching at low current sustaining the low-resistance state. It is shown that regularities governing such fluctuations in these structures substantially differ from the corresponding regularities in selenium film negistors studies earlier. According to the results of analysis, the processes initiating electrical instability and the current pinching in these structures are not associated with manifestations of heating of charge carriers by the electric field. In addition, it is found that the filament diameter virtually remains unchanged in the range of currents sustaining the low-resistance state, while the electrical conductivity of the pinching region shows a tendency to increase with current. Possible reasons for these phenomena are considered.