Effect of Post-Annealing on the Properties of Eu Doped ZnO Nano Thin Films

Europium (Eu) doped nanostructure ZnO thin films are prepared by using spray pyrolysis technique. The ZnO:Eu thin films are deposited at a substrate temperature of 623 K on glass substrates, using europium nitrate as a Eu source. The as-prepared ZnO:Eu films are annealed in air at 673 K and 723 K for 1 h. The effect of post-annealing on the structural, electrical and optical properties of the films has been studied. XRD measurements show that all the films are nanocrystallized in the hexagonal wurtzite structure and exhibit a preferential orientation along (002) plane, the intensity of preferentially oriented (002) peak is apparently improved. The resistivity of annealed film is larger than the as-deposited. ZnO:Eu film annealing at 723 K for 60 min exhibits lowest resistivity of 3.62×10-4 Ω cm. In addition, the ZnO:Eu film shows good optical transmittance of 94%.