Chemical State Analysis of Grain Boundaries in ZnO Varistors by Auger Electron Spectroscopy

✍ Scribed by Shigeru Tanaka; Chiyoshi Akita; Naoki Ohashi; Jun Kawai; Hajime Haneda; Junzo Tanaka

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 256 KB
• Volume: 105
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1993.1191

✦ Synopsis

The chemical state of grain boundaries in (\mathrm{Bi}{2} \mathrm{O}{3})-doped (\mathrm{ZnO}) ceramics was investigated by Auger electron spectroseopy. The additive Bi was segregated into grain boundaries 2 to (3 \mathrm{~nm}) thick, where oxygen deficiency occurred. Auger transitions (K L_{2,3} L_{23}) for oxygen at the grain boundaries were composed of three peaks whose relative intensities varied with the amount of the segregated Bi. Results calculated using a molecular orbital method suggested that the metal-oxygen bonding state in the grain boundary changed with increased amounts of (\mathrm{B}). The change of the bonding character was considered to be related to the formation of an interfacial state at the grain boundary causing nonlinear current-vollage characteristics. 1993 Academic Press, Inc.