On the electrical conduction and current-controlled negative differential resistance with memory in bulk samples of glassy semiconductor Cu0.05As0.50Te0.45: NTC thermistor-type behaviour

Abstract

The essential characteristics of NTC thermistor-type behaviour, besides the transition from a high resistance state to a permanent low resistance or memory state, have been analysed in the bulk modified glassy chalcogenide semiconductor Cu0.05As0.50Te0.45. Experimental results have shown a strong decrease in electrical resistivity (which ranges from 104 to 105 Omega cm in AsTe glassy alloys and its value for this alloy is 7.9*103 Omega cm at room temperature) and in the semiconductors electron mobility gap (which ranges from 0.4 to 0.5 eV for AsTe glassy semiconductors and is 0.37 eV for this alloy), due to the presence of the metallic element copper. Also, it has been shown that there are no marked non-ohmic effects in the range of voltages under study (up to 75 V for an interelectrode distance of 2.3 mm). Furthermore, the current-controlled negative differential resistance phenomenon has been justified in terms of a thermal model and confirmed by turnover voltage measurements (28.4 V for 24 degrees C and 16.9 V for 52 degrees C). Finally, several features of this glassy alloy, such as an easy synthesis, processing and low electrical resistivity values, make it appropriate for its use in the manufacture of NTC thermistors.