Electrical properties of amorphous Ge15Se60M25 where (MÂ =Â As or Sn or Bi) films

Thin film samples were prepared from the synthesized amorphous Ge15Se60M25 (where M = Sn or As or Bi) chalcogenide glass compositions by thermal evaporation technique. X-ray analysis shows the amorphous nature of the obtained films. The dc-electrical conductivity was studied for different thicknesses (89-903 nm) as function of temperature in the range (303-413 K) below Tg (glass transition temperature). The obtained results showed that the conduction activation energy has two values indicating the presence of two conduction mechanisms through the investigated range of temperature which can be explained in accordance with Mott and Davis model. The current-voltage characteristics of the investigated samples present a switching phenomenon of memory type. The mean value of the threshold switching voltage V¯th increases linearly with increasing film thickness and decreases exponentially with temperature in the investigated range below Tg. The obtained results are explained in accordance with the electrothermal model for the switching process.