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Received on: 15-06-2017 Revised on: 24-06-2017 Accepted on: 03-07-2017
ABSTRACT:
ZnO nanostructures were prepared by using hydrothermal method under different conditions. In hydrothermal method , We deposited ZnO nanorods on Cu substrate in a solution of 0.1 M of ZnCl2,it is found that the radius of tip of the nanorods found to be changing as the growth condition are changed. The effects of synthesis conditions like temperature, deposition duration and concentrations of precursors on ZnO nanostructure its growth was systematically studied by using field emission scanning electron microscopy for optimizing the conditions for getting nanorods which are more suitable for the application of electron field emission. Selected samples were characterized by X-ray diffraction, energy-dispersive X-ray spectroscopy, photoluminescence and tunneling electron microscopy. The growth mechanism of ZnO nanorods is discussed. The mechanism of ultraviolet and green emission of ZnO nanostructures also investigated using temperature dependent photoluminescence spectra.
KEY WORDS: ZnO nanorods, Hydrothermal, X-ray diffraction, Field Emission, Morphology, FE-SEM, Growth Mechanism, Photoluminescence and TEM.
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INTRODUCTION:
In the past 100 years, it has featured as subject of thousands of research papers [1]. Several techniques have been reported to grow ZnO films as well as their nanostructures. Variants of sputtering techniques have been used to synthesize ZnO thin films on Si, sapphire, glass substrates [2-6]. Chemical-vapor deposition also been widely used to synthesize crystalline ZnO thin films. Highly conducting and transparent Al-doped ZnO films have been reported using PLD and rf magnetron sputtering [7-8]. Some of the widely studied methods are hydrothermal process [9] template-based methods [10] and electrochemical method [11-12], sol-gel technique [13-14] etc. These methods provide the possibility of forming ZnO nanostructures at low temperatures. In sol-gel synthesis method, AAM has also been used as the template and immersed into suspension containing zinc acetate for 1minute, then heated in air at 120 °C for 6 hours. ZnO nanostructures are eventually obtained after removing the AAM template.
The bulk-related process is however considered to be faster in comparison with the surface-related process. For UV-detection, the fast component, due to the generation of photo carriers and their radiative and non-radiative recombination through local centres, is of greater importance [15-16]. Defects in ZnO strongly depend on the preparation and annealing conditions which in turn...