Triggering of ferromagnetism by amine functionalization on ZnO:Mn films grown by RF magnetron sputtering

Abstract

The enhanced saturation magnetization in Mn-doped ZnO (ZnO:Mn) films by Amine functionalization has been reported here. First, Mn (5 mol%, 10 mol%, and 15 mol%)-doped ZnO thin films were grown by radio-frequency (RF) magnetron sputtering which are further functionalized using trioctylamine (Amine) by spin coating. XRD pattern confirms the (002) plane of hexagonal wurtzite structure and showed that there is no significant change in the peak position after Amine functionalization. The presence of green band (GB) emission at 2.4 eV and blue band (BB) at 2.8 eV by photoluminescence study confirms the existence of oxygen vacancies in the film. Further, after Amine functionalization, quenching of green band and blue band emissions were observed. The presence of elements in the films, in particular, organic ligand, N was confirmed by XPS analysis. The VSM measurement confirms that all the grown ZnO:Mn films exhibit ferromagnetic behavior. Further, the Amine functionalization enhances the saturation magnetization (Ms) due to hybridization between 4s and 2p orbital which actually makes Zn–N and N–O bonds and induces the magnetization in the system.