Structural, nonlinear electrical characteristics, and stability against DC-accelerated aging stress behavior of Er-doped 20 nm ZnO-Bi O -Mn O -based varistors.

In this research, ZnO-Bi O -Mn O varistors manufactured from 20 nm ZnO powder and doped with different amounts of Er O were fabricated via the conventional ceramic processing method. The effect of various Er O concentrations (0.5-2.0 mol%) on the sintered density, structural improvement, and nonlinear behavior of the 20 nm ZnO-Bi O -Mn O varistors was discussed. Different Er O concentrations exerted considerable influence on the varistors. The addition of large amounts of Er O led to the inhibition of grain growth by increasing the amount of the Er O -rich spinel phase. X-ray diffraction analysis showed that the addition of Er O to the varistor systems led to the development of Er O -rich phases during sintering. During sintering, the considerable surface area of the nanoparticle powder resulted in numerous interactions in the surfaces of the ceramics manufactured from 20 nm ZnO powder. The electrical behaviors of the varistors were substantially influenced by Er O . E evidently increased from 2,144.7 to 5,482.2 V/mm with the increment in doping amount. The nonlinear coefficient also dramatically increased with the increase in Er O content. The ZnO nanoparticle-Bi O -Mn O varistors doped with 1.0-2.0 mol% Er O possessed high voltage and nonlinearity and were stable against DC-accelerated aging stress.