The point defects induced ferromagnetism in ZnO semiconductor by terbium doping via co-precipitation method

Abstract

In this work, the undoped and terbium (Tb) doped ZnO nanoparticles were synthesized by a simple chemical co-precipitation method. X-ray diffraction patterns of the undoped and Tb doped ZnO exhibit the wurtzite hexagonal crystal structure, here the changing of crystallite size and unit cell volume is noticed with doping level. The anticipated elements in the synthesized samples are confirmed using energy dispersive X-rays analysis and X-ray photoelectron spectroscopy. The hexagonal wurtzite crystal structure of the synthesized materials is also confirmed from the µ-Raman study. From photoluminescence (PL) spectra, near band edge emission (NBE) peak of ZnO and defects related peaks intensities are increased by Tb doping. The red shift (NBE) observed in Tb doped ZnO samples as compared to undoped ZnO. The PL and micro-Raman results are strongly confirming the co-existing of oxygen vacancies (VO) and zinc interstitials (Zni) defect sates in the Tb doped ZnO samples. So, the presence of these donor defect states (VO and Zni) is main reason for the strong ferromagnetism in 0.09 mol% Tb doped ZnO.