Sintered compacts of nanophase ZnO (approximately 60 nm average grain size, presintered at 600 °C) were made from powders (approximately 13 nm) prepared by the gas-condensation technique. Impedance spectra were taken as a function of temperature over the range 450-600 °C and as a function of oxygen partial-pressure over the range 10-3-1 atm (550 and 600 °C only). The activation energy was determined to be 55 kJ/mole (0.57 eV) and was independent of oxygen partial pressure. The oxygen partial pressure exponent was -1/6. Impedance spectra exhibited nonlinear I-V behavior, with a threshold of approximately 6 V. These results indicate that grain boundaries are governing the electrical properties of the compact. Ramifications for oxygen sensing and for grain boundary defect characterization are discussed.
|Number of pages||6|
|Journal||Journal of Materials Research|
|Publication status||Published - Sep 1995|
ASJC Scopus subject areas
- Materials Science(all)