Abstract
The role of different types of interfaces in a ZnO varistor material has been investigated by directly measuring the current/voltage characteristics of individual interfacial junctions. The electrically characterized interfaces were subsequently studied by analytical transmission electron microscopy. It was shown that barriers to electrical conduction form during cooling from the sintering temperature. The ZnO/ZnO junctions exhibited breakdowns at either 3.2 or 3.6 V, where the higher breakdown was observed at boundaries which contained a thin (∼2 nm) intergranular amorphous Bi-rich film, while the breakdown at 3.2 V was found at boundaries without secondary phases but which contained intergranularly segregated Bi atoms. Junctions between ZnO and intergranular Bi2O3 exhibited asymmetric current/voltage characteristics with breakdowns at 3.2 V for one polarity of the applied voltage and either 0.4 or 0.9 V for the other polarity. No varistor behavior was observed at interfaces between ZnO and pyrochlore, Zn2Sb3Bi3O14. This gives rise to a significant number of ‘‘inactive’’ grain boundaries in the material.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
