Photon-induced tunable and reversible wettability of pulsed laser deposited W-doped ZnO nanorods

¹ Groupes de Physique du Solide et Sciences des Matériaux (GPSSM), Faculté des sciences et Techniques, Université Cheikh Anta Diop de Dakar (UCAD), B.P. 25114, Dakar-Fann, Dakar, Senegal
² NANO-Sciences Laboratories, Materials Research Department, iThemba LABS, National Research Foundation, South Africa
³ Fondazione Bruno Kessler – Centro Materiali e Microsistemi, Plasma and Advanced Material, Bio-MEMS, Via Sommarive 18, 38050 Povo, Trento, Italy
⁴ Department of Physics, Institute of Applied Materials, University of Pretoria, Pretoria, 0002, South Africa

^a e-mail: ngom@emt.inrs.ca; bdngom@gmail.com

Received: 20 July 2010
Revised: 6 October 2010
Accepted: 24 March 2011
Published online: 11 August 2011

Abstract

ZnO nanorods arrays were prepared on soda lime glass substrate by pulsed laser deposition method. Hexagonal rod-like ZnO rods were obtained under different conditions. Well-defined ZnO nanorods arrays were selected among different samples having various morphologies and sizes already studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). Here, we report on the contact angle measurement (CAM) of one of these samples. A systematic change of the surface wettability is observed in W-doped ZnO nanostructures. The water contact angle (WCA) of a 1 wt.% of WO₃ target content was found to be the transition doping level from hydrophilic surface to a hydrophobic surface. We attributed the transition in surface wettability of the film with the doping to incorporation increase of tungsten into the film. Such characteristic surface wettability can play a key role in the adhesion of various layers on W-ZnO nanorods arrays for optoelectronic device applications.