International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Special Issue: 09 | Sep -2017
p-ISSN: 2395-0072
www.irjet.net
One Day International Seminar on Materials Science & Technology (ISMST 2017) 4th August 2017 Organized by
Department of Physics, Mother Teresa Women’s University, Kodaikanal, Tamilnadu, India
Surface texture and luminous analysis of Sol-Gel spin coated Dy-doped ZnO thin films S. Fathima Thaslin1, N.Anandhan1*, A.Amali Roselin1 K.P.Ganesan1, M. Karthikeyan1, T. Marimuthu1 1Advanced
Materials and Thin Film Laboratory, Department of Physics, Alagappa University, Karaikudi- 630 003, India. *Corresponding author Email: anandhan_kn@rediffmail.com ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - In this present work, we reported and
discussed the Pure and Dy (0.01, 0.02 and 0.03 at wt. %)-doped ZnO thin films deposited on a glass substrate using sol-gel spin coating technique at constant 3000rpm for the 30s and annealed at 450oC. As prepared and various concentration of Dy doped films were characterized by X-ray diffraction (XRD), UV-Visible spectroscopy (UV-Vis), Photoluminescence spectroscopy (PL) and Scanning Electron Microscopy (SEM). The XRD pattern showed that all the films are polycrystalline with hexagonal Wurtzite structure and preferentially oriented predominantly along the (101), (002) and (100) growth planes. All the prepared films exhibited low magnitude of transmittance (10 to 40%) in the UV visible range and above 450nm, the optical band gap values decreased from 3.214 to 3.053 eV with increasing doping concentration whereas the average crystalline size decreased from 36.47 to 16.46nm. The PL spectra of ZnO and Dy doped films showed a broad and intensive peak at 384nm (violet emission) is more intense than the peaks at 432nm, 413nm (violet emission) and 470nm (blue emission). The SEM micrographs indicated that the pure ZnO films have wrinkle structure, and the doped ZnO films show homogeneous root-like morphology. Key Words: Zinc Oxide, Spin coating method, Dy-doping.
1. INTRODUCTION ZnO is considered as a very promising functional electronic material due to its electrical, optoelectronic and luminescent properties [1]. ZnO is a group II-VI wide direct band gap (~3.37eV) semiconductor with a large exciton binding energy of 60meV at room temperature and hexagonal Wurtzite structure with lattice parameters of a=b= 3.250Å and c= 5.206Å, then it has attracted much attention because of its numerous prospective applications in many fields [2,3]. Especially, modified ZnO can be used as gas sensors, actuators, piezoelectric transducers, varistors [4], laser diodes, photoconductive UV detectors and high frequency surface acoustic wave (SAW) device [5]. Recently, few scientific team interested to fabricate in ZnO-based thin © 2017, IRJET
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films as flat-panel displays (FPDs) and photovoltaic applications, such as the anodic electrode of organic light emitting device (OLED) displays, the active channel layer of thin film transistors (TETs) and the transparent electrode window layer of thin film solar cells [6,7]. The ultraviolet radiation from the excited ZnO thin film is detected, which makes it possible to manufacture ultraviolet laser devices. This kind of short wave laser device will be a substitute for infrared laser memory. In addition, various light emitting devices such as blue light, green light and purple light can be produced by ZnO films [4]. Therefore, many technologies have been developed to fabricate ZnO films, such as reactive magnetron sputtering, the filtered cathodic vacuum arc (FCVA) technique, plasma assisted molecular beam Epitaxy (PMBE), pulsed laser deposition [8], buffer assisted pulsed laser deposition [6], solid state reaction method [9], coprecipitation method, metal organic chemical vapor deposition (MOCVD), spray pyrolysis technique and the solgel route. However, the sol-gel method provides the greatest possibility of synthesizing homogeneous and large area oxide films with low costs, low crystallization temperatures and high vacuum –free conditions [10]. Further, an outstanding merit of the sol-gel method is that the doping concentration of the base materials is facile and exactly controllable. Substitution of a Zn2+ ion by rare earth group ions such as Sm3+, Ln3+, Eu3+, Tb3+, Nd3+ and Dy3+ will produce extra electrons and improve optical, electrical thermal and magnetic properties [11]. The most commonly used dopant among rare earth element is Dysprosium (Dy), hence in this work, we proposed ZnO and ZnO: Dy thin films deposited by sol-gel spin coating technique and focused on investigating the effect of Dy doping concentration on the structural, morphology the sol-gel method using the spin coating technique.
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