Effect of thermal annealing on structural, optical and electrical properties of RF reactive magnetron sputtered CdO thin films

¹ Department of Physics, Osmania University, Hyderabad 500007, India
² Department of Physics, Mahatma Gandhi University, Nalgonda 508254, India

^a e-mail: anilhcu@gmail.com

Received: 13 May 2014
Revised: 27 June 2014
Accepted: 27 August 2014
Published online: 10 October 2014

Abstract

Recently, there has been a lot of interest on transparent conducting oxide (TCO) materials which have common application in solar cells and some optoelectronic devices. In this work, cadmium oxide (CdO) thin films have been deposited on glass substrates by RF reactive magnetron sputtering technique and subsequently annealed in air from 200 °C to 500 °C. The effect of annealing temperature on the structural, morphological, optical and electrical properties of CdO films is systematically investigated by X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, atomic force microscopy, UV-visible spectrophotometer and Hall effect measurements. X-ray diffraction (XRD) studies showed that the films are polycrystalline in nature with a preferential orientation along (2 0 0) plane. Atomic force microscopy studies showed that these films are very smooth with maximum root mean square roughness of 3.13 nm. The CdO films formed at annealing temperature of 400 °C exhibited optical transmittance of 84%, electrical resistivity of 1.9 × 10⁻³ Ω cm and figure of merit of 1.8 × 10⁻³ Ω⁻¹.