Structural, Optical and Magnetic Properties of Co doped ZnSe Powders

Co doped ZnSe nano crystalline powder samples were prepared by solid-state reaction method.Structural, optical and magnetic properties of pure and Co doped ZnSe powders were studied. Both Pure and doped ZnSe samples were in cubic structure. Lattice parameter and band gap of pure and doped ZnSe powders decreased with increase of Co concentration. The Raman shift in the Raman spectra of the samples confirms the Co doping in to the ZnSe lattice.Band gap of the samples decreased with increase of Co concentration. Codoped ZnSe powders exhibited half-metallic ferromagnetism at room temperature with low Co concentration and paramagnetism with high Co concentration. Introduction.Dilute magnetic semiconductors (DMS) have earned good interest in recent years because of its feasibility to have magnetic and semiconducting properties in the same materials.DMS materials are the traditional non-magnetic semiconductors doped with transition metal or rare earth metal ions at very low concentration. The host material is exhibiting some peculiar properties after doping with suitable transition metal ions[1]. DMS materials find more attention because of their applications inopto-electronics and spintronics devices, which utilizesboth the spin and charge of the electrons[2, 3]. Further these find significant role in designing of spin valves, spin light emitting diodes and ultra-fast optical switches[4]. Extensive studies had been carriedout on several II-VI DMS compounds.Among all II-VI semiconductors, ZnSe is a potential candidate to fit in various applications as solar cells [5], bio-medical tags [6]and light emitting diodes [7]. ZnSe is a blue-lasing material and can be employed in designing modulated hetero structures and optical wave guides[8]. Doping magnetic ions of +2 oxidation state into II-VI DMS such as CdSe, CdTe and ZnSe is easy.Co is one of the suitable ferromagnetic transition metal to dope in to II-VI semiconductors. Different model or mechanisms such as double exchange, RKKY carrier induced intractions, superexchange were applied to explain the origin of ferromagnetism in these II-VI DMS compounds [9, 10]. The present work focus on the effect of Co doping concentration on structural, optical and magnetic properties of Co doped ZnSe powders. Experimental details.Pure and Co doped ZnSe powder samples were prepared with different concentrations of Cobalt by solid state reaction. There sets of powders sample-1: pure ZnSe, sample2: 5at. % Co doped ZnSe and Sample-3:10 at. % Co doped ZnSe were prepared. Stoichiometric quantities of ZnSe and freshly prepared Co doped ZnSe were weighed and subjected to continuous mechanical grinding for about14-16 hours.Thepowders were sintered at 800oC for 10 hours under a 45 © 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/ Mechanics, Materials Science & Engineering, April 2017 – ISSN 2412-5954 MMSE Journal. Open Access www.mmse. xyz pressure of 10-3mbar.The pure ZnSe and Co doped ZnSe powders were characterized to study their structural, raman, optical and magnetic properties. Results and Discussion. Structural analysis.Fig.1 shows the X-ray diffraction patterns of the pureZnSe and Co doped ZnSe powder samples at different Co doping concentrations. The diffraction peaks of all the samples are found to be matched with ZnSe cubic structure pattern having JCPDS data [card no 88-2345]. The crystal structure of the host material has not been altered on increasing dopant concentration. These observations indicate that Co ions were doped in the corresponding metal sites of Zn ions.It is also observed from the XRD studies that the intensity of the peaks increased as the concentration of the dopant ions of cobalt increased from 5% to 10%. 0 500