Structural and Electrical Studies on ZnO-Based Thin Films by Laser Irradiation

Shanyue Zhao,Jian Zhang,Ruifang Chen,Yinqun Hua,Ping Ji

doi:10.1155/2016/9385725

Abstract

The effects of laser irradiation on the structural and electrical properties of ZnO-based thin films were investigated. The XRD pattern shows that the thin films were highly textured along thec-axis and perpendicular to the surface of the substrate. Raman spectra reveal that Bi2O3segregates mainly at ZnO-ZnO grain boundaries. After laser irradiation processing, the grain size of the film was reduced significantly, and the intrinsic atomic defects of grain boundaries and Bi element segregated at the grain boundary were interacted frequently and formed the composite defects of acceptor state. The nonlinear coefficient increased to 24.31 and the breakdown voltage reduced to 5.34 V.

Highlights

ZnO varistors exhibit high nonlinear coefficient, low leakage current, and high surge absorbing ability
In our previous work [20], we studied the effect of laser shock on electrical property of ZnO varistor ceramics
The nonlinear coefficient is 24.31, which increases by 40.8%, and breakdown voltage is 5.34 V, which decreases by 20.7%

Summary

Introduction

ZnO varistors exhibit high nonlinear coefficient, low leakage current, and high surge absorbing ability. They have been extensively applied on high-voltage protection of electrical equipment since the 1970s, such as inhibiting lightning overvoltage of electrical power system [1,2,3,4,5]. Tsay and Wang [18] performed ZnO thin films on glass by sol-gel and used KrF excimer laser for annealing They reported that the crystallinity levels and average crystallite size of thin films with excimer laser irradiation were greater than those of thermally annealed thin films. To the best of our knowledge, no report on ZnO-based thin film varistors with laser irradiation for low-voltage application exists. The breakdown voltage U1 mA (V) and leakage current JL (μA/mm2) are measured by piezoresistor general measuring instrument

Experiment

Results and Discussions

Conclusions