Sc2O3 doped Bi2O3-ZnO thin films varistor prepared by sol-gel method

Abstract Sc 2 O 3 modified Bi 2 O 3 -ZnO films varistors with different doping ratios were prepared by Sol-gel method. The result indicated that doping of Sc 2 O 3 significantly enhance the nonlinear current-voltage ( I-V) characteristics of Bi 2 O 3 -ZnO films. The highest non-linearity was obtained for 0.4mol% Sc content with the nonlinear coefficient α = 3.7 and 301 μA in leakage current. The grain size of ZnO phase firstly increased with Sc 2 O 3 doping when the content of Sc 2 O 3 is no more than 0.2 mol%. Upon the much more doping of Sc 2 O 3 , the growth of ZnO crystal was inhibited, leading to smaller grain size. The threshold voltage V T was inversely proportional with grain size of ZnO phase. Doping oxides gathered in the grain boundary significant impact on threshold voltage and leakage current.