Fabrication of TiO2 nanotubes by anodization of Ti thin films for VOC sensing

• Published in: Thin solid films 2011-11, Vol.520 (3), p.953-958
• Main Authors: KILINC, N, SENNIK, E, ÖZTÜRK, Z. Z
• Format: Article
• Language: English
• Subjects: Anodizing; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electrolytes; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Materials science; Methods of nanofabrication; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanotubes; Physics; Scanning electron microscopy; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films; Titanium; Titanium dioxide
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2011.04.183

Ti thin films were anodized in aqueous HF (0.5wt.%) and in polar organic (0.5wt.% NH4F+ethylene glycol) electrolytes to form TiO2 nanotube arrays. Ti thin films were deposited on microscope glass substrates and then anodized. Anodization was performed at potentials ranging from 5V to 20V for the aqueous HF and from 20V to 60V for the polar organic electrolytes over the temperatures range from 0 to 20 degree C. The TiO2 nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). It has been observed that anodization of the deposited Ti thin films with aqueous HF solution at 0 degree C resulted in nanotube-type structures with diameters in the range of 30-80nm for an applied voltage of 10V. In addition, the nanotube-type structure is observed for polar organic electrolyte at room temperature at the anodization voltage higher than 40V. The volatile organic compound (VOC) sensing properties of TiO2 nanotubes fabricated using different electrolytes were investigated at 200 degree C. The maximum sensor response is obtained for carbon tetrachloride. The sensor response is dependent on porosity of TiO2. The highest sensor response is observed for TiO2 nanotubes which are synthesized using aqueous HF electrolyte and have very high porosity.