Room temperature gas sensor based on La2O3 doped CuO thin films (original) (raw)
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Characterization of CuO thin films for gas sensing applications
Iraqi Journal of Physics, 2016
Key words Nanostructural cupric oxide (CuO) films were prepared on Si and glass substrate by pulsed laser deposition technique (PLD) using laser Nd:YAG, using different laser pulses energies from 200 to 600 mJ. The X-ray diffraction pattern (XRD) of the films showed a polycrystalline structure with a monoclinic symmetry and preferred orientation toward (111) plane with nano structure. The crystallite size was increasing with increasing of laser pulse energy. Optical properties was characterized by using UV-vis spectrometer in the wave lengthrange (200-1100) nm at room temperature. The results showed that the transmission spectrum decreases with the laser pulses energy increase. Sensitivity of NO 2 gas at different operating temperatures, (50°C, 100°C, 150°C and 200°C) was calculated. Copper oxide, thin films, structural properties, NO 2 gas. Article info.
Sensors, 2015
Cupric oxide (CuO) thin films are promising materials in gas sensor applications. The CuO-based gas sensors behaved as p-type semiconductors and can be used as part of an e-nose or smart sensor array for breath analysis. The authors present the investigation results on M-doped CuO-based (M = Ag, Au, Cr, Pd, Pt, Sb, Si) sensors working at various temperatures upon exposure to a low concentration of C3H8, which can be found in exhaled human breath, and it can be considered as a one of the biomarkers of several diseases. The films have been deposited in magnetron sputtering technology on low temperature cofired ceramics substrates. The results of the gas sensors' response are also presented and discussed. The Cr:CuO-based structure, annealed at 400 °C for 4 h in air, showed the highest sensor response, of the order of 2.7 at an operation temperature of 250 °C. The response and recovery time(s) were 10 s and 24 s, respectively. The results show that the addition of M-dopants in the cupric oxide films effectively act as catalysts in propane sensors and improve the gas sensing properties. The films' phase composition, microstructure and surface topography have been assessed by the X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) methods.
Synthesis of CuO thin film sensors by spray pyrolysis method for NO2 gas detection
Materials Today: Proceedings, 2020
The environmental pollution has become a major concern of today's era. Toxic gases such as CO, CO 2 and NO 2 are emitted from vehicles, industries, burning of crops etc. These gases are contributing a lot to the air pollution and also producing long term effect on lungs and respiratory system of human beings. Therefore gas sensing measurements for such toxic gases has received major attention. In this study, CuO is deposited by simple spray pyrolysis method and used for gas sensing measurements. The concentration of precursor solution is varied as 0.05 M, 0.1 M, 0.15 M and 0.2 M. The structural and morphological studies are done using XRD patterns and SEM images respectively. XRD patterns reveal the cubic structure of CuO. Gas sensing measurements have shown that the film deposited for 0.15 M concentration shows highest response of 56.23% for NO 2 gas. The lowest detection level has observed to be 5 ppm of NO 2. CuO has been found to be selective towards NO 2 gas.
Journal of Materials Science: Materials in Electronics, 2020
In this work, thin films of composite copper oxide-tin oxide [CuO:SnO 2 (1:1)] were prepared by radio frequency magnetron sputtering technique at room temperature on quartz glass substrates. X-ray diffraction study revealed that the as-deposited films were amorphous in nature and the crystallinity of the films was obtained by annealing the films at 1000°C. The hexagon rod-like structure, dews-like particles and cylindrical-shaped particles were observed in surface morphological study. The X-ray photoelectron spectroscopic study confirmed the formation of Cu 2? and Sn 4? states in the deposited films. The decrease in optical energy band gap with increase in RF power and annealing temperature may be due to the creation of localized states near the band edges of CuO:SnO 2. The gas sensing characteristics of the films were analysed by recording the electrical resistance variation of the films in the presence/absence of various concentrations of NH 3 gas at room temperature. The CuO:SnO 2 film exhibited a highest sensing response of 3838 for 125 ppm of NH 3 gas at room temperature. The film sustained its initial sensor response even after 6 months period for 5 repeated cycles, which ascertained the stability and repeatability of CuO:SnO 2 thin film based gas sensor.
ACS applied materials & interfaces, 2014
In the present work, perovskite LaFeO3 thin films with unique morphology were obtained on silicon substrate using radio frequency magnetron sputtering technique. The effect of thickness and temperature on the morphological and structural properties of LaFeO3 films was systematically studied. The X-ray diffraction pattern explored the highly oriented orthorhombic perovskite phase of the prepared thin films along [121]. Electron micrograph images exposed the network and nanocube surface morphology of LaFeO3 thin films with average sizes of ∼90 and 70 nm, respectively. The developed LaFeO3 thin films not only possess unique morphology, but also influence the gas-sensing performance toward NO2. Among the two morphologies, nanocubes exhibited high sensitivity, good selectivity, fast response-recovery time, and excellent repeatability for 1 ppm level of NO2 gas at room temperature. The response time for nanocubes was 24-11 s with a recovery duration of 35-15 s less than the network struct...
Sensitivity of Ce doped CuO for NO2 gas
Iraqi Journal of Physics (IJP)
In this work the structural, optical and sensitive properties of Cerium - Copper oxide thin film prepared on silicon and glass substrate by the spray pyrolysis technique at a temperature of (200, 250, 300 °C). The results of (XRD) showed that all the prepared films were of a polycrystalline installation and monoclinic crystal structure with a preferable directions was (111) of CuO. Optical characteristics observed that the absorption coefficient has values for all the prepared CuO: Ce% (104 cm-1) in the visible spectrum, indicating that all the thin films prepared have a direct energy gap. Been fabrication of gas sensors of (CuO: Ce %) within optimum preparation conditions and study sensitivity properties were examined her exposed to nitrogen dioxide (NO2) with concentration ratio of 3 %, at operating temperatures (R.T, 200 and 300 °C). It is found that the maximum sensitivity at concentration value (Ce=50 %) which it is equal to (39.15 %) at operating temperature (300 °C).
Chemical Vapor Deposition of Cu2O and CuO nanosystems for innovative gas sensors
2009 IEEE Sensors, 2009
Supported copper oxide nanosystems were synthesized by chemical vapor deposition (CVD) on Al 2 O 3 substrates and characterized by means of glancing incidence X-ray diffraction (GIXRD), secondary ion mass spectrometry (SIMS) and field emission scanning electron microscopy (FESEM). The analyses showed an evolution from polycrystalline Cu 2 O nanodeposits to CuO samples with an entangled quasi-1D morphology upon increasing the growth temperature from 350 to 550 • C. For the first time, the sensing properties of CVD copper oxide nanosystems were probed in the detection of volatile organic compounds (VOCs; e.g. CH 3 COCH 3 , CH 3 CH 2 OH). The obtained results revealed good responses even at moderate operating temperatures, with characteristics directly dependent on the system composition and nano-organization.
Sputtered copper oxide (CuO) thin films for gas sensor devices
Journal of Physics: Condensed Matter, 2006
Copper oxide (CuO) thin films were deposited using a reactive DC sputtering method for gas sensor applications. The structure of the films determined by means of an x-ray diffraction method indicates that the phase of copper oxide can be synthesized in the total pressure and temperature ranges of 6-8.5 mbar and 151-192 • C, respectively. The resistivity of the film synthesized at a substrate temperature of 192 • C increases from 0.104 to 0.51 m after absorbing CO 2 gas at 135 • C. The gas sensitivity of the film synthesized at the substrate temperature of 192 • C increases up to 5.1 in the presence of CO 2 gas at 160 • C. The gas sensitivity in the presence of N 2 gas reaches only 1.43 even at 200 • C.
Efficient room temperature carbon dioxide gas sensor based on barium doped CuO thin films
Journal of Materials Science
For a safe environment, harmful-gas sensors of low cost and high performance are essential. For CO2 gas sensing applications, Ba-doped CuO thin films with 4 mol% and 6 mol% Ba were produced on glass substrates using the successive ionic layer adsorption and reaction approach. Utilizing various techniques, crystallographic structures, nanomorphologies, and elemental compositions were examined to assess the impact of doping on the characteristics of the films. According to the structural and morphological analyses, the nanocrystalline films consisted of irregularly shaped nanoparticles, which assembled to form a rough surface with unequal grain sizes. Because of its nanoporous nature, the CuO:6% Ba thin film exhibited the most substantial nanomorphological change and the highest gas sensing capability. At varied CO2 gas flow rates, the maximum sensor response (9.4%) and Rair/RCO2 ratio (1.12) at room temperature (RT = 30 °C) were observed at 100 SCCM. By optimizing the sensor’s operat...