The effect of Cu 2 þ on structure, morphology and optical properties of flower-like ZnO synthesized using the chemical bath deposition method L.F. Koao a,n , B.F. Dejene a , H.C. Swart b a Department of Physics, University of the Free State, Qwaqwa Campus, Private Bag X13, Phuthaditjhaba 9866, South Africa b Department of Physics, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa article info Available online 19 November 2013 Keywords: ZnO Flower-like ZnO:Cu doped Chemical bath deposition method abstract In this work undoped and Cu 2 þ -doped ZnO nanostructures were prepared by the chemical bath deposition (CBD) method at 80 1C. The structural, optical and luminescence properties of the undoped and Cu 2 þ -doped ZnO nanostructures were determined by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), UV–Visible Spectroscopy (UV) and Photoluminescence spectroscopy (PL) analyses. XRD analysis showed the sample prepared were hexagonal ZnO with grain sizes in the order of 46 71 nm. The estimated grain size was found not to dependent on the concentration of the Cu 2 þ ions used. The SEM analysis revealed that the shapes of the particles were flower-like and the addition of Cu 2 þ ions influenced the morphology of the samples. In the UV–Visible study the reflectance intensity decreased with an increase in the molar concentration of Cu 2 þ and there was no shift in the absorption edges. The PL analyses revealed that the highest luminescence intensity was obtained for the undoped ZnO. Thus Cu incorporated into the ZnO resulted in the change in its morphological, structural, and optical and luminescence properties. & 2013 Elsevier B.V. All rights reserved. 1. Introduction One-dimension (1D) nanostructures represent a group of nano- material with highly anisotropic morphologies, the smallest dimen- sion falling in the range of 1–100 nm. Nowadays most of researchers focused on controlling the morphology of the ZnO for different applications [1]. It has been proven that as the particles become smaller in size, changes in the morphology and size distribution, may take on different chemical and physical properties [2]. For nanopar- ticles, both the size and the surface effects are very important. Doping nanoparticles with optically active luminescent materials manipulate the band structure of the nanocrystals and show intense emissions in a wide range of wavelength depending on the impurity type, concentration and crystal dimensions. Second, doping also play key roles in luminescence efficiency and the positions of the emission bands, thus influencing their practical application. Third, doping semiconductor nanoparticle with transitional metal ions like Mn 2 þ and Cu 2 þ yield different nanostructures [3,4]. Semiconductor nanoparticles are currently an active subject of research in nanoscience and nanotechnology [5]. ZnO is one of the most important semiconductor compounds in group II–VI. It has gained more attention in material science because of its excellent optical, electronic and other physical and chemical properties [6]. It has been widely used in near-UV emission, gas sensors, transparent conductor and piezoelectric application [7–9]. Most of the ZnO nanostructure doped with rare earth and transition metal have been synthesized by traditional high temperature solid state method and again the final products were annealed at high temperatures which is energy consuming and difficult to control the particle size and morphology properties. ZnO nanoparticles doped with rare earth or transition metal can be prepared by simple solution-based method, such as chemical precipitation [10], sol–gel synthesis [11], and solvothermal/ hydrothermal reaction [12,13] and micro-emulsion templating [14]. In the present study the ZnO powders were prepared by chemical bath deposition (CBD) method at a bath temperature of 80 1C. The final yields were annealed at ambient conditions. The CBD is one of the solution phase methods useful for the prepara- tion of compound semiconductors from aqueous solutions. The CBD method has several advantages over other well-known methods such as the use of simple equipment, low processing temperature, cost effective, uniform size and versatile. In this work we report on the structural, optical and luminescence properties of ZnO and Cu-doped ZnO nanostructure prepared by CBD. 2. Experimental setup All the chemicals used for the preparation of the nano-powders were of analytical grade. It includes zinc acetate (Zn (CH 3 COO) 2 Á 2H 2 O, copper acetate (Cu(CH 3 COO) 2 Á 2H 2 O, thiourea (NH 2 ) 2 CS) and ammonia Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/physb Physica B 0921-4526/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.physb.2013.11.025 n Corresponding author. Tel.: þ27587185300; fax: þ27587185444. E-mail addresses: koaolf@qwa.ufs.ac.za, koao@webmail.co.za (L.F. Koao). Physica B 439 (2014) 173–176