Electrical and Switching Properties of TlBiSe2 Chalcogenide Compounds

Abstract

The electrical conductivity of TlBiSe2 narrow gap semiconductors prepared by the Bridgman-Stockbarger method was investigated. The temperature dependence of the electrical conductivity was measured to establish the dominant conductivity mechanism in a temperature range between 293 K and 373 K. The conduction activation energy has a single value indicating the existence of one type of conduction mechanism in the investigated temperature range. The electrical conductivity of the sample is controlled by a thermally activated mechanism. It was also found that these samples exhibit a current-controlled negative resistance and threshold switching. The value of the threshold voltage decreases exponentially with increasing temperature. The calculated ratio of the threshold energy to the activation energy is one half, and is derived from the electro-thermal model for the switching process. Therefore, the electrical switching in the investigated samples can be explained in terms of the electro-thermal model. A possible conduction mechanism in the pre-switching state of the sample associated with the space charge limited current is described.