INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 3, ISSUE 9, SEPTEMBER 2014 ISSN 2277-8616 201 IJSTR©2014 www.ijstr.org Electrodeposition Of Zinc Selenide Films On Different Substrates And Its Characterization C.I. Nweze, A. J. Ekpunobi Abstract: Zinc Selenide (ZnSe) thin films have been successfully deposited on two different substrates using electrodeposition method at different time intervals under direct voltage of 3V. XRD pattern of the films deposited on metallic zinc substrates are indexed to cubic crystal structure at all deposition times. The dominant orientation lies on (111) plane of reflection and also more planes of reflection are formed at high deposition time which shows that polycrystalline films were deposited. XRD pattern of the films deposited on the conducting glass (Indium doped Tin Oxide (ITO)) are indexed to wurzite (hexagonal) crystal structure. Investigation reveals that both the film thickness and the grain size of the deposited ZnSe thin films increase with the deposition time for the films deposited on the two substrates. Electrical analysis of the deposited ZnSe thin films showed that the films deposited on the metallic Zinc substrate has lower electrical resistivity than the films deposited on the ITO and the resistivity increases with the increase in the thickness of the deposited films. Keywords:, Cubic Structure, Grain Sizes, ITO, XRD, Wurzite Structure ———————————————————— 1. INTRODUCTION In recent years, synthesis of materials, thin films, has attracted great interest. Also these materials have been widely studied for their unique properties, both physical and chemical. The preparation of materials with controlled sizes, morphologies and size distribution is always potentially important in the synthesis of materials suitable for optoelectronics and luminescent applications. 1-3 As one of the most important II – V group semiconductors, Zinc Selenide (ZnSe) with a room temperature bulk bandgap of 2.7eV, is a good candidate for short wavelength lasers and other photoelectronics devices such as blue-green diode lasers and tuneable mid – IR laser sources. 1,3- 5 Dimensionality, size and size distribution are known to play important roles in determining the physical and chemical properties of ZnSe thin film materials. 6 Because of the novel properties and various potential applications, ZnSe thin film materials, with typical grain size less than 10nm are attracting increasing attention from researchers all over the world. 7 Thin film materials with grain size less than 10nm exhibit properties that are often superior and sometimes completely new, in comparison with those of conventional coarse grained materials because of their small size and consequently the large volume fraction of atoms in or near the grain boundary. 7,8 Some outstanding properties of ZnSe thin film materials of smaller size include, increased strength/hardness, enhanced diffusivity, improved ductility/toughness, reduced density, reduced elastic modulus, higher electrical resistivity, increased specific heat, higher coefficient of thermal expansion, lower thermal conductivity, increased corrosion and wear resistance. 2. EXPERIMENTAL All reagents were used as purchased and solvents were distilled prior to use. ZnSe films were deposited on indium doped tin oxide (ITO) (conducting glass) and Zinc metallicsubstrates by electrodeposition method. Prior to use, the substrates were cleaned with detergent solutions, rinsed with distilled water and then rinsed with acetone, methanol and distilled water and dried before use. An area of about 6.25 cm 2 of the substrate was dipped into the electrolyte (solution). The electrodeposition bath system is composed of Zinc tetraoxosulphate VI Heptahydrate(ZnSO 4 .7H 2 O)as source of cation (Zn 2+ ), Selenium IV Oxide (SeO 2 ) as source of anion (Se 2- ), Tetra- oxo Sulphate VI acid (H 2 SO 4 ) as pH control, Potassium tetraoxo Sulphate VI (K 2 SO 4 ) as inert electrolyte and distilled water. 2.1. Preparation of solution 0.14M solution of ZnSO 4 .7H2O was prepared by dissolving 20g of it in 500ml of distilled water and it dissolved completely. 0.054M solution of SeO 2 was prepared by dissolving 3g of it in 500ml of distilled water and when thoroughly shaken, it dissolved completely in water with clear solution. Again 0.1M solution of H 2 SO 4 was prepared by dissolving 3ml of it in 500ml of distilled water and it dissolved completely. Finally 0.092M of K 2 SO 4 was prepared by dissolving 8g of it in 500ml of distilled water and it dissolved completely with a clear solution. 2.2. Electrodeposition Deposition of ZnSe on conducting glass(ITO) and Zinc metallic substrates was carried out using electrodeposition technique. 28ml, 28ml, 5ml, and 4ml solutions of ZnSO 4 .7H 2 O, SeO 2 , H 2 SO 4 , and K 2 SO 4 respectively were measure in 100ml beaker and stirred to achieve uniformity and the resultant solution was used for the deposition. The substrates (ITO and Zinc) were used as the cathode while a copper electrode was used as the anode. The deposition was done under 3V at room temperature (26 o C) and the pH of 1.8 and the deposition took place for 30secs. The same process was repeated for 60 and 90secs and in each case metallic Zinc and ITO substrates were separately used. The possible reaction mechanism is shown below: Zn 2+ + 2e − → Zn ___________________________  C.I. Nweze, A. J. Ekpunobi  Nnamdi Azikiwe University, Awka Email: ci.nweze@unizik.edu.ng