Improved semiconducting CuO/CuFe2O4 nanostructured thin films for CO2 gas sensing

doi:10.1016/j.snb.2014.07.088

Sensors and Actuators B: Chemical

Volume 204, 1 December 2014, Pages 407-413

https://doi.org/10.1016/j.snb.2014.07.088 Get rights and content

Highlights

•
Thin films were deposited by sputtering from a CuFeO₂ target.
•
Self-organized p-CuO/n-CuFe₂O₄ bilayer could be obtained by a two steps process.
•
This nanostructured bilayer was sensitive to 5000 ppm CO₂.
•
Measurement temperature, thickness and microstructure of the film were optimized.
•
A response between 45% and 50% could be obtained with Ag as additive.

Abstract

Promising results on the behavior of CuO/CuFe₂O₄ sputtered thin films as a sensing material under carbon dioxide atmospheres are presented in this article. More specifically, we report the effects of preparation parameters and microstructure of the sensing layer on the response to CO₂. FEG-SEM images and XPS measurements revealed the two-stacked layers rearrangement of samples after air annealing as a key parameter in gas sensing test. The influence of the sensing layer thickness and the influence of Ag as an additive in the film on the response are also reported. The best response was obtained at the optimal operating temperature of 250 °C with a thin film deposited under low argon pressure and low target-to-substrate distance, reaching 40% towards 5000 ppm of CO₂.

Introduction

Semiconductor nanocomposites with p–n junction were reported in the literature as the most performing materials for gas sensing regarding operating temperature and response. Ishihara et al. [1] introduced the CO₂ gas sensing using a composite oxide/BaTiO₃ junction. Several studies were performed on the comparison of different oxides combined with BaTiO₃ such as PbO, MgO, CaO, NiO or CuO [1]. As a result, CuO/BaTiO₃ exhibited the highest response to CO₂ with a relatively low operating temperature in comparison with other oxides. Other groups replaced the perovskite phase by either another perovskite phase [2] or other oxides having rutile structure [3], [4]. From then on, several research groups worked on this composite [5], [6], [7], [8] by changing the way of elaborating this material. Indeed, many studies have been carried out on thin [5], [9], [10] and thick films [1], [6], [8], [11]. Thin films show higher repeatability in fabrication process, better control on fabrication parameters and better conditions in mass production, which allows lower costs than thick film techniques. In this work, radio-frequency (RF) sputtered CuO/CuFe₂O₄ semiconductor thin films are used as sensitive material. It has been already demonstrated [12] that the CuO/CuFe₂O₄ composite was sensitive to CO₂.

In the present work, some of the key aspects concerning the electric response under CO₂ of CuO/CuFe₂O₄ thin-films are correlated with the microstructure characterization thanks to scanning and transmission electron microscopy and X-ray photoelectron spectroscopy analyses. The effects of preparation parameters, microstructure, as well as the influence of silver doping on the sensitivity of the CO₂ sensor are also described.

Section snippets

Preparation of the gas sensitive elements

Thin films were deposited by RF-sputtering technique using a CuFeO₂ ceramic target according to the preparation described by Chapelle et al. [13]. Thickness calibrations were performed with a Dektak 3030ST profilometer. Process parameters for the as-deposited samples are given in Table 1. In order to obtain the CuO/CuFe₂O₄ nanocomposite, the as-deposited films were annealed at 450 °C in air for 12 h. After heat treatment, gold interdigitated electrodes were deposited on the surface by direct

Importance of the two-stacked sensitive layers architecture: the key role of the elaboration process

The microstructure of the CuO/CuFe₂O₄ composite has been detailed previously [15] by the present authors. This material can be described as a self-organized bi-layered architecture made of a thin CuO porous cover layer on the top of a thicker CuFe₂O₄ heart layer. Due to their specific self-organization in p- and n-type layers, such films prepared by simple air annealing on as-deposited samples, exhibited significant response to CO₂ [12]. X-ray diffraction studies have shown that as-deposited

Conclusion

Thin films were deposited by RF-sputtering from a CuFeO₂ target varying argon pressure and target-to-substrate distance. The sensing layer was obtained after an air annealing for 12 h at 450 °C. Self-organization of the sample after air annealing induced a p-CuO/n-CuFe₂O₄ bilayer structure. GD-OES experiments confirm that the CuO/CuFe₂O₄ bi-layer structure is obtained on film deposited with P_0.5d₅ conditions and for thicknesses of 50 nm measured in the as-deposited state. This latter film was

A. Chapelle received her MSc in materials for energy storage and conversion from University Paul Sabatier of Toulouse in 2008. She obtained her PhD degree in 2012 from CIRIMAT laboratory, Toulouse, France. Her research is now focused on metal oxide sensors in LAAS-CNRS laboratory, Toulouse, France.

References (28)

G. Zhang et al.
Effect of particle size and dopant on properties of SnO₂-based gas sensors
Sens. Actuators B: Chem.
(2000)
J. Herrán et al.
Physical behaviour of BaTiO₃–CuO thin-film under carbon dioxide atmospheres
Sens. Actuators B: Chem.
(2007)
B. Liao et al.
Study on CuO–BaTiO₃ semiconductor CO₂ sensor
Sens. Actuators B: Chem.
(2001)
M.I. Baraton et al.
Determination of the gas sensing potentiality of nanosized powders by FTIR spectrometry
Scr. Mater.
(2001)
J. Herrán et al.
Solid state gas sensor for fast carbon dioxide detection
Sens. Actuators B
(2008)
J. Herrán et al.
Photoactivated solid-state gas sensor for carbon dioxide detection at room temperature
Sens. Actuators B
(2010)
A. Chapelle et al.
CO₂ sensing properties of semiconducting copper oxide and spinel ferrite nanocomposite thin film
Appl. Surf. Sci.
(2010)
X. Wang et al.
Transition between neck-controlled and grain-boundary-controlled sensitivity of metal-oxide gas sensors
Sens. Actuators B: Chem.
(1995)
M.H. Seo et al.
Gas sensing characteristics and porosity control of nanostructured films composed of TiO₂ nanotubes
Sens. Actuators B
(2009)
G. Sakai et al.
Theory of gas-diffusion controlled sensitivity for thin film semiconductor gas sensor
Sens. Actuators B
(2001)

G. Korotcenkov

Gas response control through structural and chemical modification of metal oxide films: state of the art and approaches

Sens. Actuators B

(2005)

K. Kiryukhina et al.

Silver oxalate-based solders: New materials for high thermal conductivity Microjoining

Scripta Materialia

(2013)

T. Ishihara et al.

Improved sensitivity of CuO–BaTiO₃ capacitive-type CO₂ sensor by additives

Sens. Actuators B

(1995)

T. Ishihara et al.

Application of mixed oxide capacitor to the selective carbon dioxide sensor

J. Electrochem. Soc.

(1991)

Cited by (51)

A review of synthesis, characterization, and magnetic properties of soft spinel ferrites
2023, Inorganic Chemistry Communications
This article has focused on the structural characteristics, magnetic behavior, synthesis procedures, and applications of the most important soft spinel ferrites. Magnetic ceramics tend to be named ferrites owing to the Latin route ferrum and are divided into hard (hexaferrites) and soft (spinels and garnets). Among soft ferrites, spinels have received special attention during the last decades. Spinels with a chemical formula of AB₂O₄ crystallize in the cubic (isometric) crystal system and are thermally and chemically stable oxides appropriate for a wide range of purposes. These applications tend to be be named microelectronic ones, magnetic memories, ferrofluids gas sensing, water purification, absorber coatings, catalysis, biomedicine, antibacterial activities, and contrast agents in magnetic resonance imaging. For this reason, this paper attempts to give an overview of the magnetic properties, structural behavior, applications, and synthetic methods of spinels.
Metal oxide resistive sensors for carbon dioxide detection
2022, Coordination Chemistry Reviews
Citation Excerpt :
Reducing the film thickness to a certain range can accelerate the response-recovery speed. The formation and decomposition of metallic carbonate are considered to be the cause of reversible reactions in the sensing mechanism [113–116], which was used by Chapelle et al. to explain the gas sensing mechanism of CuO/CuFe2O4 film for CO2 [117]. The same research group found a logarithmic relationship between the detection sensitivity of CuO/BaTiO3 and the volume concentration of CO2 at room temperature [118].
With the development of economy and society and people's pursuit of health and high living quality, more and more attention has been attracted to the detection of carbon dioxide (CO₂). Metal oxide semiconductor materials have been widely used in CO₂ detection due to their various crystal structure, numerous micro-nano morphologies, simple preparation process, and low cost. This article reviews the sensing mechanism and sensitization methods of CO₂ gas sensing materials based on metal oxides. The present works focus on the state of the art of CO₂ sensors by utilizing micro-nano hierarchical or assembled structures, doping or loading noble metals and rare earth elements, building heterogeneous structures, and using illumination excitation. The sensitization effect and mechanism are complicated and variable due to the diversity of materials and working conditions. In this paper, the CO₂ gas sensing properties of chemical resistive sensors based on various metal oxide semiconductors, such as SnO₂, ZnO, TiO₂ and BaTiO₃, are introduced in detail. Moreover, the CO₂ sensing mechanism and sensitization methods of metal oxide materials are discussed in depth, and the advantages and disadvantages of its CO₂ sensing application are summarized. Finally, future research focuses are proposed, including reducing the working temperature, improving the long-term stability and cross-sensitive anti-interference ability, demonstrating the sensitization mechanism, and constructing high-energy crystal facets.
Hybrid TiNb oxides/nitrides nanotube arrays as active catalyst supports
2022, Journal of Alloys and Compounds
In order to improve the thermal stability of anodized TiO₂ nanotube arrays, this paper proposed to fabricate the hybrid TiNb oxide nanotube arrays (TiNb ONA) on β-phase TiNb alloy plates by anodic oxidation. Then, TiNb ONA precursors were transformed into conductive nitride nanotube arrays (TiNb NNA) by nitridation at 800 °C. Introducing Nb contributes to the higher structural stability and easier nitridation of TiNb ONA compared with TiO₂ nanotube arrays. After that, the spinel CuFe₂O₄ and nanosized Re-Ni alloy were respectively loaded on TiNb ONA and TiNb NNA to form CuFe₂O₄/TiNb ONA and Re-Ni/ TiNb NNA composite electrodes, and their performances in the photoelectrochemical reduction of CO₂ and hydrogen evolution reactions were assessed respectively. Results showed that the well-maintained TiNb ONA improved the photo-response performance of the thermally-synthesized CuFe₂O₄, and TiNb NNA support also boosted the hydrogen evolution reaction because of the conductivity and catalytic activity of TiNb nitrides.
Sensitive and selective CO<inf>2</inf> gas sensor based on CuO/ZnO bilayer thin-film architecture
2022, Journal of Alloys and Compounds
A CuO/ZnO (C/Z) bilayer thin film was fabricated with a porous top CuO layer to facilitate a sensitive and selective response towards CO₂ gas. Such a sensor architecture allowed optimum oxygen and CO₂ gas adsorption in the interfacial region. The C/Z thin-film sensor exhibited a good response (47%) for 2500 ppm CO₂ at 375 °C as opposed to CuO (15%) at 300 °C and ZnO (16%) at 350 °C. The sensor was selective to CO₂ in respect of CO and CH₄ gases at 375 °C with selectivity factor κ_CO2 ∼ 5 and ∼ 8 for CO and CH₄ respectively. By analyzing the conductance-time transients for the gas, the adsorption behavior of CO₂ on the heterogenous C/Z bilayer thin-film sensor was established. CO₂ obeyed an extended Freundlich model of adsorption. Theoretical analysis of the said adsorption model was performed through which the activation energy (E_A) and heat of adsorption (Q) of CO₂ gas were estimated. A complementary relationship between E_A and Q was established. It was shown that E_A decreases with increasing concentration from 123.95 to 108.36 kJ/mol for 1000–2500 ppm CO₂ for energetically heterogeneous surfaces. Alternatively, Q values increase with increasing concentration from 59.73 to 71.65 kJ/mol for 500–2500 ppm CO₂. The CO₂ sensing mechanism was elucidated based on surface defects for CuO and ZnO. CO₂ sensing in the C/Z bilayer thin-film sensor was controlled by the adsorption of oxygen forming a space charge layer at the surface and interface of the p-n heterojunction and by band-bending as a result of the change of electron concentration across the junction.
SnO<inf>2</inf>–Co<inf>3</inf>O<inf>4</inf> pores composites for CO<inf>2</inf> gas sensing at low operating temperature
2021, Microporous and Mesoporous Materials
SnO₂ coexisted with Co₃O₄ was synthesized by using sol gel spin coating technique to enhance the CO₂ sensing ability of SnO₂–Co₃O₄ nanocomposites at lower operating temperature range. The structural properties of SnO₂–Co₃O₄ were characterized by X-ray diffraction (XRD) and diffraction peaks at (110), (101), (222), (220), (422), and (511) show tetragonal rutile and cubic structures. The scanning electron micrograph revealed that spherical and rectangular morphology was formed for the DN1, DN4, DN2 samples and on increasing Co₃O₄ volume ratio porous morphology (like spherical) was found for sample DN3. The optical band-gap was found varying with Co₃O₄ contents. The SnO₂–Co₃O₄ thin films of volume ratio 1:2 exhibited a relatively highly sensitive response to carbon dioxide gas at 30 °C. The existing studies are novel and encouraging for the understanding of SnO₂:CO₃O₄ nanocomposites based sensor for carbon dioxide gas sensing at low operating temperatures synthesized by low cost simple spin coating techniques.
Waste eggshell membrane-assisted synthesis of magnetic CuFe<inf>2</inf>O<inf>4</inf> nanomaterials with multifunctional properties (adsorptive, catalytic, antibacterial) for water remediation
2021, Colloids and Surfaces A: Physicochemical and Engineering Aspects
Dealing with water pollution is always a challenging task with the rapid development of society. The treatment of industrial wastewater usually requires the efficient and simple methods to reduce the harm to humans and the environment, and the complexity of the types of pollutants in the wastewater is a major challenge. Herein, eggshell membrane (ESM), a kind of agricultural waste with special hierarchical and porous structure, is considered as a promising bio-template for the successful fabrication of ESM-derived magnetic CuFe₂O₄ nanocomposite (defined as ESM/CuFe₂O₄). The nanocomposite exhibits unique morphological characters with 3D coral-like layered multi-channel architectures, which is completely different from that of pure CuFe₂O₄. Intriguingly, the magnetic ESM/CuFe₂O₄ can be used as a multi-functional material with enhanced adsorption, catalysis, and antibacterial performances for water remediation. The adsorption behavior of the ESM/CuFe₂O₄ to Congo red follows the pseudo-second-order kinetic model and the Freundlich adsorption isotherm with high correlation coefficients, and the maximum adsorption capability was determined to be 199.23 mg/g. The ESM/CuFe₂O₄ nanocomposite also displays the good catalytic activity and high recycling stability towards the reduction of 4-nitrophenol, and the degradation rate was reach up to 98.9 % only within 5.5 min, which is superior to some reported materials. Furthermore, it is demonstrated that the magnetic ESM/CuFe₂O₄nanocomposite possesses strong antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). In addition, some effect factors, which play an important role in enhancing the performances, are also discussed. This study provides a cost-effective approach for fabrication of advanced “green” nanomaterials with excellent performances by adding agricultural waste-eggshell membrane for water remediation.

View all citing articles on Scopus

I. El Younsi obtained her master's degree in materials engineering: thin metal layers from University of Strasbourg in 2012. She is currently pursuing her PhD degree on preparation and characterization of new sensitive layers for CO₂ gas sensors in CIRIMAT laboratory at Paul Sabatier University, Toulouse, France.

S. Vitale obtained her MSc in materials chemistry at the University of Catania (Italy) in 2011. She has worked for two years (2012–2013) at the Bern University of Applied Sciences (Switzerland), were she was involved in multilayered materials characterization by GDOES. She is currently PhD student at the Department of Chemical Sciences of the University of Catania, in LAMSUN laboratory, where she is working on surface engineering via molecular self-assembly for nanotechnology applications.

Y. Thimont is an assistant professor at the CIRIMAT laboratory (Toulouse-France) since September 2013. He received his PhD degree in chemistry of materials at the University de Caen Basse-Normandie (France) in 2009 for YBa₂Cu₃O₇ thin films depositions and characterization. He held a nine month post-doctoral position based on the study and the deposition of TCO thin films at the LRCS laboratory (Amiens-France). He then returns to Caen as temporary teacher and researcher in superconductor thematic for two years then held another post-doctoral position at Caen for one year which devoted to the synthesis and characterization of thermoelectric silicides. His research interests include the thin films synthesis and topographic, electrical, magnetic and optical characterizations.

T. Nelis received his PhD degree for work on free radical spectroscopy in Bonn, Germany. Since then he has worked several years for major scientific instrument manufactures in the field of glow discharge emission spectroscopy. Since 2011, he is professor for physics at the Bern University of Applied Sciences in Biel Switzerland. His current field of research is plasma processes for thin film deposition and surface modification.

L. Presmanes received his PhD degree, for his thesis-work on ferrite thin films for magneto-optical storage. Since 1997, he has been working in CIRIMAT laboratory at University Paul Sabatier (Toulouse) and he is also CNRS researcher since 2001. His research interests are focused on the preparation of sputtered oxide and nano-composites thin films and the study of their microstructure as well as their electrical, magnetic and optical properties. He developed sputtered ferrite thin films to be integrated as sensitive layers in magneto-optical disks and micro-bolometers (IR sensors). His work is currently focused on transparent conducting oxides and semiconductor sensitive layers for gas sensors.

A. Barnabé is a professor at the CIRIMAT laboratory, Paul Sabatier University, France. He received his PhD degree in chemistry of materials from University de Caen-Basse Normandie (France) in 1999. He held a post-doctoral position in Northwestern University, Evanston (USA), in 2000. His current research interests are mainly focused in functional metal oxide powders, ceramics and thin films prepared by PVD technique.

P. Tailhades received his PhD degree in material science in 1988 and the Habilitation à Diriger les Recherches in 1994. He is currently the vice director of the Centre Interuniversitaire de Recherche et d’Ingénierie des Matériaux (CIRIMAT), Toulouse, France. His research interests include the preparation of original metallic oxides, especially spinel ferrites, in the form of fine powders, thin films, or bulk ceramics and the study of their magnetic, electric, and optical properties. He also works on the preparation of special metallic powders. He received the silver medal of CNRS in France in 2000.

View full text

Improved semiconducting CuO/CuFe2O4 nanostructured thin films for CO2 gas sensing

Highlights

Abstract

Introduction

Section snippets

Preparation of the gas sensitive elements

Importance of the two-stacked sensitive layers architecture: the key role of the elaboration process

Conclusion

Sens. Actuators B: Chem.

Sens. Actuators B: Chem.

Sens. Actuators B: Chem.

Scr. Mater.

Sens. Actuators B

Sens. Actuators B

Appl. Surf. Sci.

Sens. Actuators B: Chem.

Sens. Actuators B

Sens. Actuators B

Sens. Actuators B

Scripta Materialia

Sens. Actuators B

Application of mixed oxide capacitor to the selective carbon dioxide sensor

J. Electrochem. Soc.

Improved semiconducting CuO/CuFe₂O₄ nanostructured thin films for CO₂ gas sensing