Calculation of the Energy Band Diagram and Estimation of Electronic Transport Parameters of Metastable Amorphous Ge2Sb2Te5

Kashem M. T. B., Muneer S., Adnane L., DİRİSAĞLIK F., Gokirmak A., Silva H.

241st ECST Meeting, Vancouver, Canada, 29 May - 02 June 2022, vol.108, pp.29-36 identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 108
  • Doi Number: 10.1149/10801.0029ecst
  • City: Vancouver
  • Country: Canada
  • Page Numbers: pp.29-36
  • Eskisehir Osmangazi University Affiliated: Yes

Abstract

© 2022 ECS - The Electrochemical Society.We calculate critical electronic conduction parameters of the amorphous phase of Ge2Sb2Te5 (GST), a common material used in phase change memory. We estimate the room temperature bandgap of metastable amorphous GST to be Eg (300K) = 1.84 eV based on a temperature dependent energy band model. We estimate the free carrier concentration at the melting temperature utilizing the latent heat of fusion to be 1.47 x 1022 cm-3. Using the thin film melt resistivity, we calculate the carrier mobility at melting point as 0.187 cm2/V-s. Assuming that metastable amorphous GST is a supercooled liquid with bipolar conduction, we compute the total carrier concentration as a function of temperature and estimate the room temperature free carrier concentration as p(300K) ≈ n(300K) = 1.69×1017 cm-3. Free electrons and holes are expected to recombine over time and the stable (drifted) amorphous GST is estimated to have p-type conduction with p(300K) ≈ 6×1016 cm-3.