Structural and Dielectric Studies of Gd Doped ZnO Nanocrystals at Room Temperature

Abstract

Gadolinium doped Zinc oxide (Zn 1 – x GdxO) nanocrystals with different percentage of Gd content ( x = 0, 0.2, 0.4, 0.6, 0.8) have been prepared by the solid state reaction method. The structural, mor-phological and chemical studies of the samples were performed by X-ray diffraction (XRD), Scanning electron microscope (SEM) and Energy dispersive X-ray (EDX) analysis. The XRD spectra confirm that all the samples have hexagonal wurtzite structure. Decrease in average crystallite size with an increase in Gd concentration is observed in XRD. SEM images show that the grain size of undoped ZnO is larger than the Gd doped ZnO, specifying the hindrance of grain growth upon Gd doping. The chemical composition of the samples was confirmed using Energy dispersive X-ray (EDX) analysis. The variation of dielectric constant ( ε r ), dielectric loss (tan δ ) and AC conductivity as a function of frequency is studied at room temperature in a frequency which ranges from 100 Hz - 4.5 MHz by using LCR Hi TESTER. All the samples exhibit the normal dielectric behavior, i.e. decreases with increase in frequency which has been explained in the light of Maxwell-Wagner model. The dielectric constant and dielectric loss can be varied intensely by tuning Gd concentration in Zn 1 – x Gd x O compounds.