UV irradiation influence on the structural and optical properties of CdO thin films

¹ “Al. I. Cuza” University, 11 Carol I Bldv, 700506, Iasi, Romania
² Institute of Macromolecular Chemistry “Petru Poni”, Aleea Gr. Ghica-Voda nr. 41A, 6600 Iassy, Romania

^a e-mail: dantuscristian@uaicphys.co.cc

Received: 9 February 2011
Revised: 27 April 2011
Accepted: 16 May 2011
Published online: 21 July 2011

Abstract

Polycrystalline Cd thin films were evaporated in a vacuum onto glass substrates at Cd source temperature of 770 K. The as-deposited Cd films were subjected to a gradual heating at the rate of 5 K/min, up to a temperature of 650 K and were then maintained at this temperature for 5 min. Then, the respective samples were cooled down to room temperature at the same rate. The obtained CdO thin films were UV irradiated for 2 h (150 W mercury lamp, 3.18–3.65 eV). By means of XRD, AFM and XPS techniques, the structural characteristics of the typical obtained CdO samples before and after UV treatment were investigated. The obtained results indicate that the UV treatment induces a recrystallization process: changes in sample morphology, surface roughness and crystallite size and orientation. XRD and XPS studies evidenced an improvement in crystalline structure and stoichiometry. UV irradiated sample shows photo-catalytic properties.