Amorphous p‐Type Conducting Zn–xIr Oxide (x > 0.13) Thin Films Deposited by Reactive Magnetron Cosputtering. Issue 2 (11th November 2021)

• Record Type: Journal Article
• Authors: Zubkins, Martins; Timoshenko, Janis; Gabrusenoks, Jevgenijs; Pudzs, Kaspars; Azens, Andris; Wang, Qin; Purans, Juris
• Is Part Of: Physica status solidi. Volume 259:Issue 2(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-11-11
• Subjects: amorphous thin films -- p-type conductivity -- reactive magnetron co-sputtering -- RMC-EXAFS -- X-ray absorption spectroscopy -- zinc–iridium oxide; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.202100374
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : Zinc–iridium oxide (Zn–Ir–O) thin films have been demonstrated as a p‐type conducting material. However, the stability of p‐type conductivity with respect to chemical composition or temperature is still unclear. In this study we discuss the local atomic structure and the electrical properties of Zn–Ir–O films in the large Ir concentration range. The films are deposited by reactive DC magnetron co‐sputtering at two different substrate temperatures—without intentional heating and at 300 °C. Extended X‐ray absorption fine structure (EXAFS) analysis reveals that strongly disordered ZnO4 tetrahedra are the main Zn complexes in Zn–Ir–O films with up to 67.4 at% Ir. As the Ir concentration increases, an effective increase of Ir oxidation state is observed. Reverse Monte Carlo analysis of EXAFS at Zn K‐edge shows that the average Zn–O interatomic distance and disorder factor increase with the Ir concentration. We observed that the nano‐crystalline w ‐ZnO structure is preserved in a wider Ir concentration range if the substrate is heated during deposition. At low Ir concentration, the transition from n‐ to p‐type conductivity is observed regardless of the temperature of the substrates. Electrical resistivity decreases exponentially with the Ir concentration in the Zn–Ir–O films. Abstract : Zinc–iridium oxide films demonstrate p‐type conductivity regardless of the substrate temperature. X‐ray absorption spectroscopy reveals that strongly disordered ZnO4 tetrahedra are the main Zn complexes in the films. Reverse Monte Carlo analysis of extended X‐ray absorption fine structure spectra shows that the average Zn–O interatomic distance and disorder factor increase with the Ir concentration.