Int. J. Adv. Sci. Eng. Vol.5 No.3 1072-1076 (2019) 1072 E-ISSN: 2349 5359; P-ISSN: 2454-9967 Rajesh et al., International Journal of Advanced Science and Engineering www.mahendrapublications.com ABSTRACT: To date, thin film deposition with low cost technique and desired process parameters has been intensively studied. The cost effective sol-gel spin coating has been widely used for the deposition of different types of elements in thin film form. ZnO thin films can also deposit with the application of this technique. The prepared solution led to deposit high crystalline ZnO thin films without annealing at elevated temperature. The crystal structure of deposited films was characterized by X-ray diffraction technique. Narrowed and high intensity diffraction peak at 34.4° clearly indicated that the films exhibit hexagonal wrutzite structure of ZnO. The optical properties of these films were typically studied using UV- vis NIR double beam spectrophometer, the optical transmittance in the visible region was more than 90% and showed sharp absorption edge. SEM images showed earth warm like wrinkle surface. The four probe method revealed electrical resistivity of 1. 4 Ω cm. KEYWORDS: Sol-gel deposition, ZnO film, structural, optical, electrical properties. https://doi.org/10.29294/IJASE.5.3.2019.1072-1076 © 2019 Mahendrapublications.com, All rights reserved *Corresponding Author: kathiravan626@gmail.com Received: 19.01.2019 Accepted: 18.02.2019 Published on: 27.02.2019 Production of Transparent Conducting ZnO Thin Films with Preheated Temperature by Sol-Gel Spin Coating Technique S. Rajesh 1 , K. Saravanakumar 2 , T. Jayakumar 3 , V. Kathiravan* 4 , S. Praburaj 5 , M. Aasha 6 1 Department of Physics, Pachaiyappas college for men, Kanchipuram- 631 501, Tamil Nadu, India. 2 Department of Physics, Mahendra Engineering College (Autonomous), Namakkal, 637503, Tamil Nadu, India. 3 Department of Physics, Government Arts College (Autonomous), Kumbakonam-612001, Tamil Nadu, India. 4,5,6 Department of Physics, Annai College of Arts & Science, Kovilacheri, Kumbakonam- 612 503, Tamil Nadu, India. 1. INTRODUCTION In recent past, ZnO thin films have been received increasing attention for arrays of applications in opto- electronics device such as transparent electrode for solar cell [1], light emitting diodes [2], flat panel displays [3]. ZnO has wide band gap (3.37 eV) with high excitonic binding energy (60 meV) and n-type conductivity [4, 5]; these peculiar properties exhibit high transmittance in visible region and high electrical conductivity. Besides, ZnO is a low-cost, non-toxic, high chemical and thermal stability [6-9]. Several methods have been employed for deposition of ZnO thin films such as sputtering, spray pyrolysis, pulsed laser deposition (PLD) and sol-gel processing. Of these methods, sol-gel has attracted interest for depositing thin films because of its significant advantages: simplicity, inexpensive, large area coating and ease dope. In sol-gel deposition, most of the researchers are found amorphous ZnO films before post annealing treatment. To get high quality ZnO films after as-prepared, the films were annealed at high temperatures. Kumar et al. [10] reported the sol-gel deposited films are in amorphous state, which are transformed into crystalline state during the annealing process. Bu et al. [11] reported that the coated films were sintered in two step process. Initially, the film was sintered at 250 °C to evaporate the solvent and then annealed at 550 °C to crystallite the film. There are no studies on ZnO film properties in literature for as- prepared film, because of the poor in crystalline nature of films before annealing. In the present work, therefore, we concentrated to deposit high crystalline quality ZnO thin films with good optical transmittance without the post annealing treatment. The films deposited at preheated temperature of 200 °C were studied their structural, optical and surface morphology properties and reported. 2. EXPERIMENTAL 2.1 Deposition of thin films Un-doped ZnO and F doped ZnO thin films were deposited by a sol-gel technique. The host and dopant materials were zinc acetate dehydrate (C4H10O6Zn) and ammonium fluoride (NH4 F), respectively. Ethanol was used as solvent and monoethanol amine (MEA) was used as stabilizer. For the preparation of starting precursor, 0.1 M of zinc acetate dihydrate and 0.1 M of ammonium fluoride (5 at. %) were dissolved in combining of 19 mL ethanol and 1 mL of monoethylene amine. This solution was stirred at 60 °C for 2h to get clear and homogeneous solution, while solution container was wrapped tightly with aluminum foil to avoid the evaporation of solvent, which maintaining the appropriate viscous of solution. Then the solutions were aged for 24 h at room temperature. The glass substrates were immersed in the diluted HCl for 2 h to etch dust particle if any on surface to be coated and then subjected to the ultrasonic waves and then thoroughly cleaned with acetone. The precursor solution was dropped on to the glass substrate, which was rotate at the speed of 5000 rpm for 60 s by a spin coater. After the coating, the film was preheated at 200 °C for 10 min to evaporate the solvent and organic residuals as well as for