IOSR Journal of Research & Method in Education (IOSR-JRME) e-ISSN: 2320–7388,p-ISSN: 2320–737X Volume 5, Issue 3 Ver. III (May - Jun. 2015), PP 16-20 www.iosrjournals.org DOI: 10.9790/7388-05331610 www.iosrjournals.org 16 | Page Synthesis and Characterization of CuS/PVA Nanocomposite via Chemical method Zainab J. Shanan College of science for Women, University of Baghdad, Jadriya, Baghdad, Iraq Abstract: Nanocomposite of copper sulfide (CuS /PVA) have been synthesized according to chemical precipitation method at temperature 65ºC by simple reaction between copper acetate (Cu (ac)) and thiourea (H2NCSNH2) at pH=9. Polyvinyl Alcohol (PVA), used as capping agent, was found to play a key role in the confinement process. The characterization of the product was done by UV-VIS spectroscopy, atomic force microscopy (AFM) and x-ray diffraction (XRD). The X-ray diffraction showed the covellite phase of copper sulphides with hexagonal crystal structure. The sizes of the sample as prepared were calculated by Debye-Scherrer formula according to XRD spectra. A UV-VIS optical spectroscopy study was carried out to determine the band gap of the nanocomposite CuS to be about 3.3 eV. Keywords: Nanocomposite; Atomic Force Microscopy; Polyvinyl Alcohol. I. Introduction Copper sulphides belonging to the I-IV compound semiconductor material [1,2] and are among the chalcogenides compounds with several application in Nanosciences. They are found very useful in coating solar energy conversion systems and solar controlled devices. The chalcogenides are also used in the fabrication of microelectronic devices, optical filters as well as in low temperature gas sensor applications [2]. Moreover, ternary copper halcogenides like copper indium diselenide and copper indium gallium selenides, in recent times, are now widely used in the fabrication of solar photovoltaic cells [3]. Special attention is given to the study of copper sulphide thin films due to the discovery of the CdS/CuxS heterojunction solar cell [2]. Synthesis and characterization of nanocrystals of semiconducting metal sulphides have been an intense field of research due to their interesting properties and potential applications [4-5]. Copper sulphide has fairly complex crystal chemistry owing to its ability to form sub- stochiometric compounds CuxS (2≥x≥1) [6]. CuS phase exists in two forms, the amorphous brown chalcocite CuS and green crystalline covellite [7]. CuxS has many forms in bulk at room temperature. They are chalcocite (orthorhombic Cu2S), djurleite (mono-clinic-prismatic Cu1.95S) etc. [8, 9]. In the chalcocite group, Cu2-xS (0≤x≤0.6), eight compounds exist. They are γ-chalcocite Cu2S (low, orthorhombic), β-chalcocite Cu2S (high, hexagonal), djurleite Cu 1.97S, digenite Cu1.80S, roxbyite Cu 1.78S, anilite Cu 1.75S, geerite Cu 1.60S and spionkopite Cu 1.60S. While γ-chalcocite, djurleite and anilite form low temperature phases, the tetragonal Cu 1.96S phase, low digenite, Cu 1.8S and roxbite, Cu 1.75S form metastable phases [10]. II. Experimental CuS nanopaarticles were prepared by reacting copper acetate Cu (ac) with thiourea (H2NCSNH2) in the presence of polyvinyl alcohol (PVA) as capping agents. A 3% PVA solution was mixed with copper acetate solution to act as capping agent. Equivolume and eqimolar (0.01M) solution of copper acetate and thiourea were used for the synthesis. Ammonia was added to the PVA mixed copper acetate solution to make copper ion complex and the pH was kept at 9. Then thiourea solution was added drop wise for the formation of final copper sulphide matrix solution. The synthesized copper sulfide solution became greenish in color. X-ray diffraction was recorded with an automated X'pert Philips diffractometer with Cu Kα radiation beam λ=1.5406 ەA .The optical absorption measurements obtained from the colloidal solution were performed in UV- Vis spectrophotometer SP-3000 plus, OPTIMA INC. Japan .In order to investigate the surface morphology and surface roughness, the atomic force microscopy (AFM) observations were performed using an SPM model AA 3000, Angstrom Advanced Ins.v ,USA . The AFM images were analyzed with the Pro Scan software, calculating the root mean square surface roughness value. III. Result and Discussion 1 XRD studies The crystalline nature of the prepared nanocomposite CuS is evident from the x-ray diffraction pattern Figure (1). The most significant feature within the observed pattern, at 2θ=21.10997, is assigned to the (004) reflection of the hexagonal primitive covellite CuS crystal structure as observed by ICSD # 041975card no. 78-