Fabrication and Characterization of Hydrophilic TiO2 Thin Films on Unheated Substrates Prepared by Pulsed DC Reactive Magnetron Sputtering

M. Horprathum,P. Limsuwan,P. Chindaudom,A. Pokaipisit,V. Patthanasettakul,P. Eiamchai,N. Nuntawong,P. Limnonthakul

doi:10.1155/2010/841659

Abstract

TiO2 thin films were deposited on unheated silicon wafers (100) and glass slides by a pulsed DC reactive magnetron sputtering in an ultrahigh vacuum (UHV) system. The effects of both an operating pressure and deposition time on film structure, surface morphology, and optical property were studied. The film structure and microstructure were characterized by grazing‐incidence X‐ray diffraction (GIXRD) technique and transmission electron microscopy (TEM). The surface morphology was investigated by field emission scanning electron microscopy (FE‐SEM). The optical property of the TiO2 thin films was determined by spectroscopic ellipsometry (SE). The water contact angle measurement was also used to determine hydrophilicity of the films after exposed to UV light. The results suggested that the TiO2 thin film at less than 40 nm was amorphous. As the thickness was increased, the mixture of anatase and rutile phases of TiO2 began to form. By reducing the operating pressure during the film deposition, the rutile phase component can also be enhanced. Both the increased film thickness and decrease operating pressure were the critical factors to improve the hydrophilicity of the TiO2 thin films.

Highlights

Titanium dioxide (TiO2) is a well-known photocatalyst with good chemical stability, high refractive index, and good mechanical hardness
This work mainly focused on the effects of the operating pressure and the deposition time which critically affect the structural, optical, and hydrophilic properties of the TiO2 thin films prepared by the pulsed DC reactive magnetron sputtering
The structures of TiO2 thin films deposited at two different operating pressures and at equal thickness were compared

Summary

Introduction

Titanium dioxide (TiO2) is a well-known photocatalyst with good chemical stability, high refractive index, and good mechanical hardness. The surface energy is minimized and the surface becomes hydrophilicity For these unique properties, TiO2 can be used for preparation of self-cleaning, antifogging, and antibacterial coating. TiO2 can be used for preparation of self-cleaning, antifogging, and antibacterial coating Such TiO2 thin films can be prepared by many methods which include sol-gel [4, 5], metal-organic chemical vapor deposition (MOCVD) [6], molecular beam epitaxy (MBE) [7], ion-beam assisted deposition [8, 9], and sputtering technique [10,11,12,13,14]. This work mainly focused on the effects of the operating pressure and the deposition time which critically affect the structural, optical, and hydrophilic properties of the TiO2 thin films prepared by the pulsed DC reactive magnetron sputtering

Experimental Details

Results and discussion

Conclusions