Role of Native Defect in Near Room Temperature CH<sub>4</sub> Sensing Using Nanostructured V<sub>2</sub>O<sub>5</sub>
Reshma P. Radhakrishnan, Arun K. Prasad, Sandip Dhara
Abstract
Native defects are highly prevalent in vanadium pentoxide (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> ) as it can easily get converted into reduced oxides. The role of defects in gas sensing properties of V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> nanostructures, however, are not well understood. In the present report, effect of native defects on near room temperature sensing is reported for the first time. Hydrothermally grown V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> nanoparticles with substantial sensor response to CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> close to room temperature at 50 °C is presented. Fast response and recovery times of 43 s and 75 s, respectively, for 500 ppm CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> gas at optimum operating temperature of 150 °C were observed. Temperature dependent photoluminescence studies were carried out to understand the role of native defects and their emission behavior leading to carrier saturation in realizing optimum operating temperature.