Doping effect of Dy on leakage current and oxygen sensing property of SrTiO₃ thin film prepared by PLD

Abstract

Polycrystalline Dy-doped SrTiO₃ thin films deposited by pulsed laser deposition (PLD) on CeO₂-buffered yttria-stabilized zirconia (YSZ) single crystal substrates showed oxygen sensing characteristics at room temperature. The oxygen gas sensing characteristics depended on the amount of Dy-doping, and 1.5 mol% Dy-doping was most effective. The oxygen gas sensing characteristics were closely related to leakage current characteristics of Dy-doped SrTiO₃ thin film deposited on ZnIn₂O₄/YSZ/Si(001) substrates. The suppression of leakage current by Dy-doping suggests that Ti⁴⁺ is substituted by Dy³⁺, and the Dy³⁺ acts as an acceptor. Further doping of Dy³⁺ brought about the increase of the leakage current, and it lowered the oxygen gas sensitivity.