Magnetic and optical studies of transition metals-doped ZnS nanostructures

Abstract

One of the challenges for the development of future electronic technologies is the realization of devices that control not only the electron charge, as in present electronics, but also its spin, setting the foundation for future spintronics. In this scenario dilute magnetic semiconductor materials (DMS), with electron charge and spin characteristics, are the ideal candidates to meet these challenges. The spin can induce new functionalities in the spintronics devices which have no analogue in today’s semiconductor devices. The study of DMS at nanoscale can provide the possibility of tuning the lattice constants and band gap parameters by varying the amount of the dopant atom and the size of nanomaterials. However, till date, few efforts have been made towards exploiting the room temperature ferromagnetism in transition metals-doped semiconductor nanostructures, but, a concrete universal model is yet to be developed to explain the possible cause of ferromagnetism in doped semiconductor nanostructures. Therefore, it has stimulated a great interest in both basic and applied research. In present thesis work, the structural, optical and magnetic properties of transition metals-doped ZnS nanostructures, nanoparticles and nanorods, synthesized using chemical synthesis route, have been analyzed. The properties have been studied using various techniques viz. transmission electron microscope (TEM), High resolution (HRTEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), UV-Visible spectroscopy (UV-Vis.), photoluminescence spectroscopy (PL) and vibrating sample magnetometer (VSM). The properties of transition metals-doped ZnS nanostructures found altered than their bulk and undoped counterparts. Magnetism has been observed at room temperature in case of undoped and transition metals-doped ZnS nanostructures; however, the dopants concentration, leading to various exchange interactions, plays a decisive role in inculcating altered optical and magnetic character in ZnS.