Enhanced optical and electrical properties of Y-doped ZnO nanoparticles having different Y concentrations

Abstract

In this study, undoped ZnO and yttrium (Y)-doped ZnO (YZO) nanoparticles having different Y dopant concentrations (Zn_1−xY_xO; x = 0.005, 0.01, 0.015, 0.02) were successfully synthesized by sol–gel dip-coating method. Structural characterizations of the obtained samples were examined with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analyses. SEM analysis shows that the synthesized nanoparticles are mostly dot-like structures. The sizes of nanostructures decrease with increasing Y-doping concentration up to 2 mol % Y and XRD results show that all of samples have wurtzite hexagonal structure of ZnO with (002) c-plane orientation. According to EDS results pure YZO samples are obtained. Optical transmittances of all samples were investigated in the range of 350–750 nm at room temperature. The average optical transmittances of YZO samples in the visible region are approximately over 90%, but the transmittance starts to decrease for Zn_0.98Y_0.02O sample. Also, it was observed that the optical transmittances of Y-doped samples are higher than that of undoped ZnO. The electrical properties of YZO samples were obtained by resistance measurements at room temperature. The resistivity of samples was found to be 2.25 × 10⁻³, 1.43 × 10⁻³, 7.8 × 10⁻³, and 1.3 × 10⁻³ Ω-cm for Zn_0.995Y_0.005O, Zn_0.99Y_0.01O, Zn_0.985Y_0.015O and Zn_0.98Y_0.02O, respectively. All these results show that surface, structural, electrical and optical properties of ZnO samples can be improved with doping Y up to 2 mol % concentrations.