Memory switching of ZnGa2Se4 thin films as a new material for phase change memories (PCMs)

ZnGa2Se4 thin films were prepared by using thermal evaporation technique. X-ray diffraction patterns revealed the amorphous nature of the as- deposited films. The dc conductivity was studied as a function of temperature and thickness. The obtained results of dc electrical conductivity showed its semiconductor behavior and can be explained according to Mott and Davis model. The conduction activation energy ΔEσ has one value for each thickness indicating the presence of one conduction mechanism through the studied range of temperature. Both dynamic and static I–V characteristic curves of amorphous ZnGa2Se4 thin films for switching and memory behavior have been studied as a function of thickness in the range (136–260 nm) and temperature in the range (305–373 K). I–V   characteristic curves showed a memory switching at the threshold point [turnover point (TOP)] from the high resistance state (OFF state) to the low resistance state (ON state). The mean value of threshold voltage V¯th increases linearly with increasing the film thickness while decreases exponentially with the increase of temperature. The mean value of the threshold electrical field E¯th decreases exponentially with increasing temperature. The values of threshold activation energy ɛ and threshold resistance activation energy ΔER were calculated. The rapid transitions between the high resistive and conductive states were attributed to an electrothermal model initiated from Joule heating of current channel.

Research highlights▶ Preparation and characterization of ZnGa2Se4 thin film. ▶ Dc electrical conductivity and the conduction mechanism. ▶ Memory switching device. ▶ Electro-thermal model for switching breakdown.