Chalcogenide Letters Vol. 7, No. 4, April 2010, p. 269 - 273 OPTICAL, STRUCTURAL AND MORPHOLOGICAL STUDIES OF BEAN- LIKE ZnS NANOSTRUCTURES BY AQUEOUS CHEMICAL METHOD RITA JOHN * , S. SASI FLORENCE a Department of Theoretical Physics, University of Madras, Guindy Campus, Chennai, Tamilnadu, India a Department of Physics, Mother Teresa Women’s University, Kodaikanal, Tamil Nadu, India The ZnS semiconducting nanoparticles were synthesized by simple chemical reaction of ZnCl 2 and Na 2 S in aqueous solution. The main advantage of this method is the use of non toxic precursors and water is used as solvent. The as-prepared ZnS nanoparticles have average size of 12 nm. The structural, morphological, chemical composition and optical properties of the nanoparticles have been investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infra Red Spectroscopy (FTIR), Ultra Violet Spectroscopy (UV) and Photoluminescence (PL). (Received April 2, 2010; accepted April 15, 2010) Keywords: Semiconductors, ZnS, Aqueous chemical method, Nanostructure 1. Introduction Nanosized inorganic semiconducting materials have been generating an extensive interest in recent years owing to their structure, chemical and physical properties, which are different from those of the bulk materials. ZnS has a wide band gap of 3.5 - 3.8 eV at room temperature and the band gap can be tuned in the UV region. It is an important inorganic material for a variety of applications including photoconductors, solar cells, field effect transistors, sensors, transducers optical coatings and light-emitting materials [1-4]. It has been investigated extensively, because of its potential optical applications [5-7]. ZnS doped with various transition metal ions such as manganese is an efficient light emitting material [8-10]. Nanostructured materials have been synthesized by many simple methods such as wet chemical method [11-12], solid-state reaction method [13], etc. The purpose of the present work is to synthesize ZnS nanoparticles using aqueous chemical method and investigate the properties such as size, structure, band gap, absorption and luminescence. 2. Experimental details The synthesis of ZnS nanoparticles was carried out by aqueous chemical method using zinc chloride and sodium sulfide as source materials. All the reagents were of analytical grade and used without further purification. The entire process was carried out in distilled water for its inherent advantages of being simple and environment friendly. All steps of the synthesis were performed at low temperature and ambient conditions. In a typical preparation, solution of 1 M zinc chloride was prepared in 100 ml of deionized water and then the solution of 1 M sodium sulfide was added drop wise to the solution which was kept on stirring using a magnetic stirrer at 70 0 C, which resulted in formation of ZnS nano colloid. The nanoparticles were collected by centrifugation at 2000 rpm for 15 minutes. And further purification was made by ultrasonic bath. The resultant product was finally dried at 120 0 C for 2 hours.