Abstract
We report a novel mechanism to effectively detect LP gas based on surface modification through sulphidation followed by passivation of electrodeposited n-type cuprous oxide (Cu2O), forming a thin film nCu2O/p-CuxS semiconducting heterostructure. Electrochemically deposited n-type cuprous oxide (n-Cu2O) thin films on Ti substrates in acetate bath were sulphided using Na2S to fabricate n-Cu2O/pCuxS heterostructures. Subsequent passivation of these thin film structures using (NH4)2S vapor enhanced the sensitivity (fractional change in thin film resistance) when exposed to liquefied petroleum (LP) gas. Scanning electron micrographs (SEM) confirmed that typical unsulphided n-type Cu2O thin films exhibit polycrystalline surface morphology, while SEM of both sulphided and passivated thin films revealed micro/nano-crystalline surface morphological features with porous structures. As expected, the thin film structures obtained through sulphidation followed by passivation of n-type Cu2O films decreased the resistance (100 kΩ) in comparison to the resistance (1 MΩ) of the unsulphided n-type Cu2O thin films. Upon exposure to LP gas, the resistance of these thin film structures increased while, sensitivity to LP gas depended on the sensing temperature. Exposure of thin film structures fabricated by electrodepositing n type Cu2O thin films for 45 min, sulphided and passivated for 5 s and maintained at a sensing temperature of 45 oC to LP gas with a flow rate of 2.5 ml/min recorded the highest sensitivity of 48 %.
Highlights
Liquefied Petroleum (LP) gas is used worldwide for domestic, commercial and industrial purposes and is a highly flammable gas
Scanning electron micrographs (SEM) picture of Cu2O thin films (a) n-type thin films fabricated in acetate bath (b) sulphided and passivated
Untreated Cu2O thin films showed a resistance ~1 MΩ which reduced down to ~ 100 kΩ after sulphidation and passivation
Summary
Liquefied Petroleum (LP) gas is used worldwide for domestic, commercial and industrial purposes and is a highly flammable gas. There are many parameters of materials that are important for gas sensing applications, for example, adsorption ability, catalytic activity, sensitivity and thermodynamic stability are some of them. Many different metal oxide materials are favorable in some of these properties (Bochenkov & Sergeev, 2010; Korotcenkov, 2007; Wang, et al, 2010; Shishiyanu, et al, 2006). Due to this situation, more recent works focus on composite materials, such as, ZnO-CuO, SnO2-ZnO andα-Fe2O3/ZnO (Yoon, et al, 1998; De Lacy Costello, et al, 1999; Chen, et al, 2008). It is important to note that the detection of simple gases, through semiconducting metal oxides often require elevated temperatures (Arafat, 2012; Gopel & Schierbaum, 1995; Sun, et al, 2012; Bochenkov & Sergeev, 2010)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
