Effects of Gibbs free energy difference and oxygen vacancies distribution in a bilayer ZnO/ZrO2 structure for applications to bipolar resistive switching

Muhammad Ismail, Mehr Khalid Rahmani, Sobia Ali Khan, Junheok Choi, Fayyaz Hussain, Zahida Batool, Anwar Manzoor Rana, Jinju Lee, Hyojong Cho, Sungjun Kim

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

We investigated the effects of the Gibbs free energy difference (∆Go) and distribution of oxygen vacancies in a bilayer ZnO/ZrO2 structure. The device exhibited high endurance characteristics of up to 1000 DC repetitive resistive cycles, long retention (104), and a low coefficient of variation of SET and RESET-voltages (6% and 5%, respectively). In addition, X-ray photoelectron spectroscopy (XPS) analysis of the ZnO and ZrO2 layers indicated that the oxygen vacancies/defects in the ZnO layer (44.13%) were larger than in the ZrO2 layer (34.11%), and that the oxygen ions of O[sbnd]Zr (65.89%) were larger than those of O[sbnd]Zn (55.87). This XPS analysis confirmed that the differing oxygen vacancy distributions in the ZnO/ZrO2 layer are responsible for improving the switching performance. The switching behavior, endurance, and retention time strongly depend on the types of electrode and switching materials used. We obtained qualitative and quantitative evidence that ∆Goof the oxide materials plays a significant role in determining the resistive switching characteristics. Bipolar switching mechanisms are explained by considering ∆Go in the ZnO and ZrO2 layers, where the formation and rupture of conductive filaments are caused by oxygen vacancies. Our findings suggest that a bilayer ZnO/ZrO2 structure is promising for application to non-volatile memory.

Original languageEnglish
Article number143833
JournalApplied Surface Science
Volume498
DOIs
StatePublished - 31 Dec 2019

Keywords

  • Bilayer structure
  • Effect of Gibbs free energy
  • Oxygen vacancies
  • ZnO/ZrO film

Fingerprint

Dive into the research topics of 'Effects of Gibbs free energy difference and oxygen vacancies distribution in a bilayer ZnO/ZrO2 structure for applications to bipolar resistive switching'. Together they form a unique fingerprint.

Cite this