Structural, optical and dielectric study of Cu doped ZnO nanoparticles synthesised by high energy ball milling

Abstract

Cu doped ZnO nanoparticles abbreviated as Zn1–xCuxO (x = 0, 0.01 and 0.03) were synthesised by high energy ball milling (HEBM) technique. The structural, morphological, optical and dielectric properties of the synthesised nanoparticles were carried out by XRD, FTIR, UV-Vis and impedance analyser, respectively. The incorporation of the dopant Cu into ZnO hexagonal wurtzite structure has been verified by X-ray diffraction (XRD). The effect of Cu doping on the structural bonding of ZnO has been verified by Fourier transformation infrared (FTIR) spectra. The XRD spectra shows that all the synthesised nanoparticles are single phase, hexagonal wurtzite structure and belong to the space group of p63mc. Compared to pure ZnO (18 nm), the crystallite size of Cu doped ZnO (15 nm) is smaller and peak broadening exists in the system. A similar feature of FTIR spectra has been observed for all samples, which supports the hexagonal wurtzite structure of ZnO even after Cu doping. The band gap (Eg) of ZnO decreases with Cu doping which can be attributed to sp-d exchange interaction between the ZnO band electrons and localised d electrons of Cu2+ ions. The dielectric constant of ZnO decreases with Cu doping.