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Resistive room temperature LPG sensor based on a graphene/CdO nanocomposite
摘要： The authors decribe an ultra-sensitive, room temperature, flexible transparent LPG sensor based on the use of a CdO/graphene nanocomposite. The graphene prevents the accumulation of CdO, enhances the surface area, and acts as a gas sensing material. FESEM images show a uniform decoration of CdO nanoparticles on graphene. The CdO/graphene composite was deposited as a film on interdigitated electrodes (IDEs) which then were used for chemiresistive sensing of liquid petroleum gas (LPG) by using a four probe technique. A Resistivity decreases significantly upon exposure to a LPG. The electrical resistance measurement at a constant bias voltage of 0.5 V. The sensor of type CdO/graphene (1 wt.%) exhibits a sensitivity of 600 ppm of LPG at 27 °C. It is a highly selective, stable and sensitive to low concentration of LPG even at room temperature.
关键词： Gas sensor,CdO,Liquefied petroleum gas,Graphene,Flexible
更新于2025-09-23 15:23:52
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Effect of Nd doping on structural and opto-electronic properties of CdO thin films fabricated by a perfume atomizer spray method
摘要： A perfume atomizer-assisted spray pyrolysis method was employed to fabricate undoped and neodymium (Nd)-doped cadmium oxide (CdO) thin films. X-ray diffraction results reveal that all the films are polycrystalline with a cubic structure with a preferential orientation along the (200) direction. Scherrer’s formula was used to calculate the crystallite size of Nd-doped CdO films. Energy dispersive spectroscopy results show that Cd, Nd and O elements are present in Nd-doped CdO thin films. The optical absorption of the doped films is increased along with increasing Nd-doping level. The prepared CdO thin films have a high absorption coefficient in the visible region and the optical band gap is decreased on increasing Nd doping content. The electrical carrier concentration (n) of the deposited films is increased with increasing Nd doping concentration. Photoconductivity studies of a nanostructured Al/Nd–n-CdO/p-Si/Al device showed a non-linear electric characteristics indicating diode-like behaviour. Prepared Nd:CdO films could increase the photo-sensing effect of this n-CdO/p-Si heterostructure. These Nd-doped CdO thin films may open a new avenue for photodiode application in near future.
关键词： optical and electrical properties,Nd:CdO,thin films,spray using perfume atomizer
更新于2025-09-23 15:23:52
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A New Catalyst Ti Doped CdO Thin Film for Non-Enzymatic Hydrogen Peroxide Sensor Application
摘要： A new material, Ti doped CdO (Ti: CdO) semiconductor, is firstly reported by this work for electrochemical non-enzymatic hydrogen peroxide (H2O2) sensor applications which was deposited by a simple, versatile and cost-effective chemical spray pyrolysis method on indium doped tin oxide (ITO) substrate. In the basic studies, first, the withstanding of cubic crystal phase along with worthy crystalline nature is discerned on CdO film after Ti doping, here only the preferentially orientated (200) diffraction plane shifted to (111). Subsequently, the irregular spherically shaped CdO nanoparticles (NPs) morphology changed as nearly uniform size with Ti doping is noticed with respect to thermal pyrolytic decomposition process. The existence of Ti atoms in Ti: CdO film is authentically identified and confirmed using EDX and XPS studies respectively. The absorption and emission properties of CdO and Ti: CdO films are studied and confirmed their narrow band gap nature. Importantly, the Ti: CdO film shows pronounced electrocatalytic activity for the reduction of hydrogen peroxide (H2O2) as compared to pure CdO. Hence, the non-enzymatic electrochemical sensing of Ti: CdO electrode shows a lower detection limit 0.4 μM with the linear range of 10-190 μM which displayed a fast amperometric response for 5 s with sensitivity of 0.27 μA μM-1 cm-2 toward H2O2 detection. This result will boost exploring a new opportunity for the deposition of other metal oxides and semiconductors by using a simple chemical spray pyrolysis method for detection of non-enzymatic H2O2 sensor applications.
关键词： H2O2 sensor,and selectivity,Chemical spray pyrolysis,Ti: CdO thin film
更新于2025-09-23 15:23:52
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Effect of nanostructured metal oxides (CdO, Al2O3, Cu2O) embedded in PVA via Nd:YAG pulsed laser ablation on their optical and structural properties
摘要： The physiochemical properties of Polyvinyl Alcohol (PVA) film was enhanced by embedding with nanostructured metal oxides (CdO, Al2O3, and Cu2O) via one-pot and green method, nanosecond Nd:YAG pulsed laser ablation in liquids technique (PLAL). This process was carried by ablation of metal targets (cadmium, copper, and aluminum) immersed in PVA solution by high intensity pulsed laser in the focusing condition. The enhancing of the PVA properties were appeared by studying the structure, optical and morphology of the prepared films before and after embedding by several technique as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–Visible, Photoluminescence (PL), Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). From structural investigation, the XRD patterns showed a reduction of CdO, Al2O3, and Cu2O nanoparticles within PVA chain. From optical investigation, the interaction and the structural modifications occurred between PVA chains and each metal oxide nanoparticles appeared in stretching vibration bands, the optical energy band gap (Eg) values by using Tauc equation equaled to 2.33, 3.63, and 3.54 eV for the oxide of Cd, Al, and Cu, respectively, are a good agreement with previous work, and the Photoluminescence spectra showed decreasing in emission intensity in the case of embedding with metal oxides. From morphological investigation, the FE-SEM images showed a homogeneous distribution with spherical shape of metal oxides through the polymer of PVA. The qualitative and semi-quantitative elemental analysis of the prepared samples via EDX technique confirmed the embedding of the metal oxide in the PVA structure. This work helps to open the route to produce various properties of PVA by embedded with different nanostructured metal oxides.
关键词： Laser ablation,Al2O3,Nd:YAG,Metal oxides,nanosecond,PVA,Nanomaterials,CdO,Cu2O
更新于2025-09-16 10:30:52
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rGO modified nanoplate-assembled ZnO/CdO junction for detection of NO2
摘要： The triadic composite of ZnO/CdO heterojunction decorated with reduced graphene oxide (rGO) was prepared using a one-step hydrothermal method. The characterizations of morphology, structure and composition to the composite were undertaken by XRD, Raman, SEM, TEM, XPS, UV-vis spectra. The sensing experimental data indicate that the highest response of the ZnO/CdO/rGO (1.0 wt%) composite to ppm-level NO2 is 8 times and 2 times higher than pure ZnO and ZnO/CdO junction, respectively. The composite not only exhibits fast response time and recovery time, high response, but also reveals outstanding stability and repeatability at an operating temperature of 125°C. The sensing mechanism also has been discussed in detail in the work. The enhancement in gas sensing properties is credited to the development of ZnO/CdO heterojunction and the decoration of rGO with high conductivity. The logarithm of sensitivity in the range of 0.4-2.4 ppm NO2 shows good linear dependence, indicating that the composite based sensor can be used to quantificationally detect low concentration of NO2.
关键词： Graphene,NO2,rGO,ZnO/CdO,Gas sensor
更新于2025-09-16 10:30:52
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Controlled sol–gel synthesis of oxygen sensing CdO?:?ZnO hexagonal particles for different annealing temperatures
摘要： CdO : ZnO hexagonal particles were synthesized by a sol–gel precipitation method at di?erent annealing temperatures. A mixed crystal phase of cubic and wurtzite structures was observed from X-ray di?raction patterns. The micrographs showed hexagonal shapes of the CdO : ZnO nanocomposites particles. The energy dispersive X-ray spectroscopy mapping images showed a uniform distribution of the Cd and Zn. The CdO : ZnO nanocomposite pallet annealed at 550 (cid:1)C has an electrical resistance of 0.366 kU at room temperature. The nanocomposites showed an excellent sensing response against oxygen gas with a sensing response of 47% at 200 (cid:1)C for the CdO : ZnO particles annealed at 550 (cid:1)C. The sensor response and recovery times were found to be 43s and 45s, respectively. The sensor response was due to the sorption of oxygen ions on the surfaces of the CdO : ZnO hexagonal particles.
关键词： sol–gel,annealing temperature,hexagonal particles,oxygen sensing,CdO : ZnO
更新于2025-09-16 10:30:52
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SILAR Controlled CdS Nanoparticles Sensitized CdO Diode Based Photodetectors
摘要： In this research, we have produced Al/CdS nanoparticles-CdO/p-si/Al photodetetor and investigated its optical and electrical characteristics for various optoelectronic applications. The CdO thin film was covered by using sol-gel spin coating method onto the silicon, followed by CdS nanoparticles constitution by the help of SILAR technique. In order to examine the morphological and optical characteristics of fabricated photodetector, the field emission scanning electron microscopy and UV-Vis spectroscopy were utilized, and the band gap of the prepared film was determined as 2,17 eV with the help of these analyzes. The current behavior against the varying voltage values were investigated for the different intensities of solar light conditions and the significant diode parameters were computed by the use of this measurements. As a result of this computation, the barrier height value was found to be 0.49 eV while the ideality factor value was 3.2, and the photoresponse of the photodetector was measured as approximatelly 2.65 × 103. Besides, the transient photocurrent and photocapacitance charactersitics were examined for distinct light conditions. Finally, the interface states were calculated from the capacitance/conductance–voltage (C/G–V) measurements.
关键词： Optical characteristics,SILAR method,Sol-gel method,CdO thin film,Electrical characteristics,CdS nanoparticles
更新于2025-09-12 10:27:22
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Enhancements of p-Si/CdO Thin Films Solar Cells with doping (Sb, Sn, Se)
摘要： Un-doped and (Sn, Sb, Se ) doped (CdO) cadmium oxide was prepared as a thin film (500nm). (Cd) thin films was deposit under vacuum (10-5 mbar) on Si wafer and glass substrate. Thermal oxidation at 473K converted the Cd thin films to CdO as n-type mode attached to p-Si as a heterojunction structure. This research contribute structural, electrical, and optical properties for doped CdO on glass. The structure properties of the thin film by the (X-ray diffraction) illustrated a polycrystalline structure. The (AFM) results indicate that the grain size of the films CdO have a different size with respect to doping atoms (Sn, Sb, Se ). UV-Visible spectroscopy analysis shows that the optical band gap values with the range of ( 2.1 -1.6 eV) for pure and dopant films. The value of band gap for CdO films is decreased when 0.5wt% of adding impurities (Sn, Sb, Se ). The optical absorption showed in the range 300-1100 nm for 0.5 wt% (Sn, Sb, Se) doping. Electrical properties of p-Si /n- CdO heterojunction were investigated by I-V (with and without illumination) at different doped atoms. The characteristics of the photovoltaic measurements (Jsc, Voc, FF, η) are determined for all samples.
关键词： solar cell,thin films,n- CdO /p-Si,heterojuncion
更新于2025-09-12 10:27:22
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Complexities of atomic structure at CdO/MgO and CdO/Al 2O 3 interfaces
摘要： We report the interface structures of CdO thin films on (001)-MgO and (0001)-Al2O3 substrates. Using aberration corrected scanning transmission electron microscopy, we show that epitaxial growth of (001)-CdO||(001)-MgO occurs with a lattice misfit greater than 10%. A high density of interface misfit dislocations is found to form. In combination with molecular dynamics simulations, we show that dislocation strain fields form and overlap in very thin heterostructures of CdO and MgO (< 3 nm). On the c-Al2O3 substrate, we find that CdO grows with a surface normal of [025]. We show that three rotation variants form due to the symmetry of the sapphire surface. These results contribute insights into the epitaxial growth of these rock-salt oxides.
关键词： CdO,epitaxial growth,Al2O3,scanning transmission electron microscopy,molecular dynamics simulations,MgO,interface structures
更新于2025-09-09 09:28:46
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Mg doped CdO thin films grown on glass substrate by spray pyrolysis method
摘要： The undoped and various magnesium (Mg) doped cadmium oxide (CdO) thin films were synthesized by spray pyrolysis technique. Structural, optical and morphological examinations of the samples were carried out via various instruments. X-ray diffraction (XRD) and Raman spectroscopic measurements of the samples were performed to obtain structural properties. Ultraviolet (UV)-visible and photoluminescence (PL) spectroscopy measurements as well as scanning electron microscopy (SEM) were employed to characterize optical and morphological properties of the undoped and Mg doped CdO thin film. XRD measurements revealed that both the undoped and Mg doped CdO thin films demonstrated a cubic structure and had preferential orientations along the (200) plane. In the Raman spectrum, it was observed that the peak (266 cm?1) of the first peak belonging to the CdO thin film disappeared and the second main peak (908 cm?1) shifted to higher energies with the Mg dopant. As a result of the absorbance measurements, the band range of the samples showed a shift of the band gap from 2.15 eV to 2.43 eV with the Mg dopant, and the Burstein-Moss effect indicated a shift to gray scale and decreased from 67% to 59% in transmittance measurements. The PL results exhibited that both the undoped and Mg doped CdO thin films had a UV emission of 394 nm (3.15 eV), blue emission of 434 nm (2.86 eV), blue-yellow emission of 540 nm (2.30 eV), 735 nm (1.69 eV) and emission of 782 nm (1.59 eV). The SEM measurements indicated that the CdO thin films changed from pyramidal structures to random shape with Mg dopant.
关键词： optical properties,Mg dopant,CdO thin film
更新于2025-09-09 09:28:46