Lattice defects and oxygen vacancies formulated ferromagnetic, luminescence, structural properties and band-gap tuning in Nd3+ substituted ZnO nanoparticles

Abstract

ZnO and Zn1-xNdxO nanoparticles synthesized using the microwave assisted co-precipitation method were probed using XRD, HRTEM, UV–Vis spectroscopy, Raman spectroscopy, Photoluminescence spectroscopy and SQUID for robust and sufficient optical, structural, and magnetic profiles. The Hexagonal wurtzite structure of all the nanoparticles with a spherical shape and size in the 20-14 nm range was confirmed by XRD and HRTEM. The lower angle shift of the diffraction peaks indicated the interstitial addition of Nd3+ and collated to the lattice expansion. Urbach energy with its tail slope was used to define structural disorder in materials, and it increased with doping and decreased the optical band gap due to band-tail and tail-tail transitions. Broadening and asymmetry of the first-order E2 (high) phonon Raman mode identified structural disorder. The Spatial correlation model with changes in line center position, line width, and asymmetry of the E2 (high) phonon mode gave dopant created disorder. PL studies were used to determine the oxygen vacancy concentration, other defects, and excitation wavelength in all the nanoparticle samples that could be used as white light display devices. Magnetic studies with the BMP model were employed to confirm that Nd3+ doping leads to an increase in RTFM. Oxygen vacancies were considered to have a critical role in generating weak FM behavior in Zn1-xNdxO nanoparticles.