Impact of divalent dopant Ca$^{2+}$ on the electrical properties of ZnO by impedance spectroscopy

[摘要] The electrical properties of Zn$_{1−x}$Ca$_x$O ($x = 0, 0.01$, 0.02 and 0.03) nanoceramics synthesized by solidstate reactionmethod were investigated by complex impedance spectroscopy (CIS) from room temperature to 500$^{circ}$C. Structural analysis of the synthesized material using the X-ray diffraction technique suggests that they exhibit a single phase with hexagonal wurtzite structure. Experimental results indicate that the synthesized material shows temperature-dependent relaxation phenomena. The variation of frequency exponent ($s$) with temperature shows the presence of thermally activated polarization mechanism in the synthesized sample. Dielectric constant was found to decrease with increase in frequency and temperature for Ca-doped samples. Ca-doped ZnO sample shows dielectric loss at lower temperature than that of pure ZnO.

[学科分类] 材料工程

[关键词] XRD;Zn$_{1−x}$Ca$_x$O;impedance spectroscopy.