Effect Of Film Thickness On The Structural Morphological And Optical Properties Of Nanocrystalline ZnO Films Formed By RF Magnetron Sputtering

R. Subba Reddy1*, A. Sreedhar1, A. Sivasankar Reddy2, S. Uthanna1*

1Department of Physics, Sri Venkateswara University, Tirupati 517 502, India

2Division of Advanced Materials Engineering, Kongju National University, Budaedong, Cheonan city, South Korea

Adv. Mater. Lett., 2012, Current Issue, 3 (3), pp 239-245

DOI: 10.5185/amlett.2012.3329

Publication Date (Web): Jun 10, 2012

E-mail: sbbreddy82@gmail.com, uthanna@rediffmail.com

Abstract


Zinc oxide (ZnO) thin films were formed by RF reactive magnetron sputtering onto p-type silicon and glass substrates held at room temperature. The thickness of the films deposited was in the range 160 – 398 nm. The thickness dependence structural, morphological and optical properties of ZnO films were systematically investigated. The maximum crystallite size of 21 nm observed at films thickness of 231 nm by X- ray diffraction. Scanning electron microscopic analysis revealed that the growth of nanowires in all the films. The root mean square roughness of the films increased from 7.3 to 53 nm in the thickness range of investigation. Fourier transform infrared analysis confirmed the Zn-O bonding located at wavenumber of 413 cm-1. The average optical transmittance of the films was about 89 % in the visible region. The optical band gap of the ZnO films decreased from 3.14 to 3.02 eV with increase of film thickness from 160 to 398 nm respectively.

Keywords

Thin films, sputtering, ZnO films, structure, optical properties.

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