DC electrical conductivity and switching phenomena of amorphous Te81Ge15Bi4 films

Thin films of Te81Ge15Bi4 were prepared from its bulk glass by thermal evaporation method. Amorphous structure of the prepared films was examined by X-ray diffraction (XRD). Differential thermal analysis (DTA) was carried out to obtain the glass transition temperature Tg. DC conductivity σdc was studied as a function of temperature below Tg in the range (303-393 K) and in thickness range (143-721 nm). The results obtained are based on the model of Mott and Davis. The obtained films were found to exhibit memory type of electrical switching behaviour. The threshold switching voltage Vth is found to be reduced exponentially with temperature and enhanced with the thickness of the film in the considered range. The obtained results of the switching behaviour are interpreted according to the electrothermal model motivated by Joule heating.