Electrical Properties of Amorphous Titanium Oxide Thin Films for Bolometric Application

Abstract

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&#x2009;<svg style="vertical-align:-0.0pt;width:12.9875px;" id="M1" height="11.425" version="1.1" viewBox="0 0 12.9875 11.425" width="12.9875" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,11.363)"><path id="x3A9" d="M719 146l-18 -146h-243l-5 18q2 4 17 25t24 36l25 42t26.5 52.5t21 56.5t16 65t5.5 68q0 121 -55.5 194.5t-149.5 73.5q-95 0 -150 -72t-55 -199q0 -54 18.5 -114t36.5 -94t48.5 -82.5t32.5 -51.5l-7 -18h-244l-17 146l27 1q17 -49 31.5 -62t45.5 -13h89l-21 21t-26 26.5&#xA;l-26 29t-28 35.5l-23 37.5t-20.5 43t-12 45.5t-5.5 51q0 133 88 218.5t219 85.5q132 0 218 -83t86 -218q0 -40 -11.5 -78t-33 -71.5t-39 -56t-44 -51t-32.5 -35.5h84q35 0 48 12t31 63z" /></g> </svg>&#x2009;cm to 10.1&#x2009;<svg style="vertical-align:-0.0pt;width:12.9875px;" id="M2" height="11.425" version="1.1" viewBox="0 0 12.9875 11.425" width="12.9875" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,11.363)"><use xlink:href="#x3A9"/></g> </svg>&#x2009;cm. At the same time, the temperature coefficient of resistivity and activation energy vary from &#x2212;1.2&#x25; to &#x2212;2.3&#x25; and from 0.09&#x2009;eV to 0.18&#x2009;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&#x2009;K to 373&#x2009;K.