Rare-earth oxide doped ZnO nanostructures for high-performance varistors

Zinc oxide (ZnO) based varistors are widely recognized for their nonlinear electrical properties, making them suitable for surge protection devices. Their performance, however, strongly depends on the microstructural modifications induced by suitable dopants. The present study focuses on the effect of rare-earth oxide doping, specifically praseodymium oxide and cerium, on the electrical characteristics of nano-structured ZnO varistors. The nanostructures were synthesized using a cost-effective solution combustion technique and systematically doped with these oxides. Microstructural analysis revealed a significant refinement of grain size, accompanied by improved grain boundary density. Electrical measurements demonstrated a remarkable enhancement in the breakdown voltage as compared to pure ZnO, confirming the strong influence of the dopants on varistor performance. The enhancement in breakdown voltage from 320 V for pure ZnO to nearly 3948 V and 3958 V for nano praseodymium oxide and cerium oxide filled Zinc oxide varistor samples were achieved respectively, confirming the influence of the dopants on varistor performance.  The findings indicate that incorporation of rare-earth oxides offers an effective strategy for tailoring ZnO-based varistors with superior surge protection capabilities, making them promising for advanced electronic and power system applications.

Dr. M. G. Veena’s research interests include nanocomposite materials for electrical insulation/electronics applications and MEMS sensors. She carried out post graduate research work at Nanyang Technological University Singapore, hold Ph.D from University of Mysore and published 35 peer reviewed papers. Presently professor, in the department of Electronics and Communication Engineering, JSS Science and Technology University. Visited Australia, Bangkok, IIT Guwahati for paper presentation and received a citation award for IEEE published article. Best outstanding researcher award KIER, outstanding branch counselor award from IEEE Mysore subsection. Life member of ISTE, member IEEE, IEEE-WIE (Women-in-Engineering) advisor and IEEE-SJCE student branch counselor.