Temperature dependence of Ge₂Sb₂Te₅ conductivity and its change during aging

Abstract

Results of studies of conductivity activation energy and its evolution during the aging process are presented for the common phase change material Ge2Sb2Te5. The evolution of temperature dependence of conductivity during quasi-isothermal annealing are interpreted in the framework of simple Arrhenius model as the change of two corresponding parameters: activation energy and pre-exponential factor. It is shown, that the change in resistivity of the Ge2Sb2Te5 during aging is attributed to the simultaneous change of both parameters of the Arrhenius equation, that is, activation energy and pre-exponential factor. Temperature dependencies of those parameters are shown as well, and the Meyer-Neldel rule for conductivity of Ge2Sb2Te5 is tested on the basis of the obtained data.

Temperature activated conductivity of Ge2Sb2Te5: connection to the variation of Fermi level and implications on resistance drift

“…and we suggested such explanation before, obtaining E MN ≈ 25 meV [25]. However, the non-linear behaviour evident in figure 3 is not readily incorporated in the framework of existing MNR theories [47].…”

“…This observation is in line with the results of [24,26] where it is shown that for Ge 2 Sb 2 Te 5 the resistance drift is controlled by variation of activation energy solely, the prefactor remaining constant. Alternatively, the prefactor value for Ge 2 Sb 2 Te 5 can saturate rapidly [25], while activation energy continues to change during resistance drift. Bandgap E g of Ge 2 Sb 2 Te 5 , as well as other PCM materials, increases during aging [31,32,45], and it is commonly accepted that the activation energy for conductivity follows this increase.…”

“…A large body of experimental studies of resistance drift focuses on the kinetics of this process [20,21], structural studies [22], and first principles modelling [23]. Approaches to study evolution of temperature dependence of resistance are also proposed [24,25]. A simple parameterisation based on Arrhenius equation dominates the latter, allowing extraction of activation energy for conductivity and its time dependence during drift, together with the pre-exponential factor.…”

Effect of lanthanum cerium methionine on the properties of natural rubber

“…Rare earth ions and ligands are combined by electrostatic effect when coordinated, and the bond type is ionic. 25 Therefore, lanthanum cerium methionine is very stable and will not dissociate weakly acidic methionine ions. Furthermore, acidic substances have a delayed effect on rubber vulcanization.…”