%0 Journal Article
%T Electrical Properties of Amorphous Titanium Oxide Thin Films for Bolometric Application
%A Yongfeng Ju
%A Mahua Wang
%A Yunlong Wang
%A Shihu Wang
%A Chengfang Fu
%J Advances in Condensed Matter Physics
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/365475
%X We report the electrical conduction mechanism of amorphous titanium oxide thin films applied for bolometers. As the O/Ti ratio varies from 1.73 to 1.97 measured by rutherford backscattering spectroscopy, the resistivity of the films increases from 0.26£¿ £¿cm to 10.1£¿ £¿cm. At the same time, the temperature coefficient of resistivity and activation energy vary from £¿1.2% to £¿2.3% and from 0.09£¿eV to 0.18£¿eV, respectively. The temperature dependence of the electrical conductivity illustrates a thermally activated conduction behavior and the carrier transport mechanism in the titanium oxide thin films is found to obey the normal Meyer-Neldel Rule in the temperature range from 293£¿K to 373£¿K. 1. Introduction Titanium dioxide (TiO2) is one of the most widely studied transition metal oxide semiconductors due to its nontoxic nature, chemical stability, and commercial availability at a low cost, robust, and general reactivity. During the past decades, TiO2 thin films have attracted much interest because it has a wide range of promising energy and environmental applications, such as hydrogen generation by water splitting [1], photocatalytic water purification [2], dye-sensitized solar cells [3], and gas sensors [4]. Recently, few people have fabricated amorphous nonstoichiometric titanium dioxide, (a- , where is smaller than 2) thin films by different methods and pointed out that a- thin films are potential thermal sensing material for an uncooled IR bolometer imager [5]. However, the effect of the deposition process on the film structure, composition and electrical properties of this material such as resistivity, temperature coefficient of resistivity (TCR), and activation energy, have not been illustrated up to now, and these factors are very crucial for the detectivity of thermal IR detectors. thin films can be prepared by sol-gel [6], hydrothermal [7], chemical and physical vapor deposition [8]. Reactive sputtering is a commonly used physical vapor deposition method to grow dense and uniform metal oxide films for industrial application [9, 10]. In this process, a metal target is sputtered in an atmosphere consisting of argon and oxygen, this allows higher deposition rates than does the sputtering of an oxide target [10]. It has been experimentally established that the oxygen partial pressure (pO2) during sputtering has the most significant effect on the structure, phase composition, and electrical properties of thin films [11]. TiO2 is electrically insulating with an extremely high resistivity above 108£¿ £¿cm, but the suboxidized TiO2 with an excess of titanium
%U http://www.hindawi.com/journals/acmp/2013/365475/