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Graphical abstract Highlights • Ti doped CdO is firstly reported for electrochemical non-enzymatic H 2 O 2 sensor applications. • Fabricated nanostructured thin films were directly exploited as working electrodes toward the detection of harmful H 2 O 2 gas. • Ti: CdO film exhibits pronounced electrocatalytic activity for the reduction of H 2 O 2 when compared to pure CdO. Abstract A new material, Ti doped CdO (Ti: CdO) semiconductor, is firstly reported by this work for electrochemical non-enzymatic hydrogen peroxide (H 2 O 2) 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 under 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 (H 2 O 2) than pure CdO. Hence, the non-enzymatic electrochemical sensing of Ti: CdO electrode shows a lower detection limit, broad linear range, rapid response time and high sensitivity toward H 2 O 2 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 H 2 O 2 sensor applications. [ABSTRACT FROM AUTHOR]

The pure and Cu-doped CdO thin films with various doping concentrations (0.5 to 2 wt%) were deposited on amorphous glass substrates by a chemical spray pyrolysis technique for hydrogen gas sensor application. The crystallinity, morphology, optical and electrical properties of the CdO thin films were effectively modified by Cu doping. The CdO film exhibited a cubic crystal structure, which is retained after Cu doping with significant changes in the preferential orientation of the crystallographic plane. The SEM and AFM images clearly revealed that the grain size and roughness of the CdO film changed with the Cu doping level. The expected element compositions were initially identified by EDAX and then authentically confirmed by XPS to determine its binding energy states. The optical transmittance and near band edge emission (NBE) bands of the CdO film were significantly decreased by Cu doping level. The minimum resistivity (2.01 × 10−3Ω cm) as well as good mobility (19.5 cm2 V−1 s−1) and maximum carrier concentration (1.98 × 1020 cm−3) were obtained for the 1 and 0.5 wt% Cu-doped CdO thin films. The Cu-doped CdO thin films exhibit better hydrogen gas sensing behaviour than that of pure CdO film. Finally, it is concluded that the maximum sensitivity is vividly achieved for the Cu-doped CdO thin film at 1 wt%. [ABSTRACT FROM AUTHOR]

Transparent conducting cadmium oxide (CdO) and Fe (0.5, 1, 1.5 and 2 wt%) doped CdO thin films were deposited on glass substrate using facile chemical spray pyrolysis technique. The influence of Fe doping on the structural, morphological, optical and electrical properties of CdO thin films were systematically investigated using different characterization techniques such as X-ray diffraction (XRD), atomic force microscope (AFM), UV–vis transmittance and Hall measurement respectively. The XRD patterns clearly reveal the pure and Fe doped CdO films are polycrystalline nature along with cubic crystal structure. AFM images show the roughness of the CdO thin film decreases with respect to Fe doping concentration. The surface structure of the 1 wt% Fe doped CdO film was investigated by X-ray photoelectron spectroscopy (XPS). Optical transmittance of the CdO thin film decreases with increasing of Fe doping concentration. The optical band gap value of the CdO thin film gradually decreases from 2.61 to 2.18 eV with increasing Fe doping concentration. From Hall measurement, the minimum value of resistivity is obtained for (7.67×10 −4 Ω cm) 1 wt% of Fe doped CdO thin film. Finally, the ethanol sensor behaviour was observed using home-built sensor unit. The maximum ethanol gas response of 56.12% is observed for 1 wt% of Fe doped CdO thin films. This result suggests the Fe doped CdO is one of the promising material in sensor applications. [ABSTRACT FROM AUTHOR]

Transparent conducting CdO thin films were deposited on to glass substrates by spray pyrolysis technique. The depositions were carried out at different substrate temperatures with varying film thickness. The effects of substrate temperature on structural, optical and electrical properties of CdO thin films were systematically studied. The CdO films were polycrystalline in nature with cubic crystal structure showing preferential orientation along (111) direction. Wettability results confirmed that the hydrophobic character of CdO thin film is enhanced with increase in substrate temperatures. The average transmittance is about 80 %, thus the films are transparent in the visible region. The optical band gap value of the CdO films increased from 2.24 to 2.34 eV with increase in the substrate temperature from 200 to 350 °C. Surface morphology studies reveal that the grain size and roughness of the films are increased with increase in the substrate temperature. The minimum value of electrical resistivity of the films is 1.40 × 10 Ω cm obtained at 350 °C. The maximum ethanol sensitivity of 33.45 % is observed for the substrate temperature of 300 °C. Thus the results authenticate that the substrate temperature influences the structural, optical, electrical and sensing properties of the deposited films. [ABSTRACT FROM AUTHOR]

Transparent and conducting cadmium oxide (CdO) and manganese doped CdO (Mn: CdO) thin films were deposited using a low cost spray pyrolysis method on the glass substrate at 300 °C. For Mn doping, various concentrations of manganese acetate (1–3 wt%) was used in the spraying precursor solution. The structural, electrical and optical properties of CdO and Mn: CdO films were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), UV–vis and Hall measurement. X-ray diffraction study reveals that the CdO and Mn: CdO films are possessing cubic crystal structures. SEM and AFM studies reveal that the grain size and roughness of the films are increased with increasing Mn doping concentration. Optical transmittance spectra of the CdO film decreases with increasing doping concentration of manganese. The optical band gap of the films decreases from 2.42 eV to 2.08 eV with increasing concentration of manganese. A minimum resistivity of 1.11×10 −3 Ω cm and maximum mobility of 20.77 cm 2 V −1 s −1 is achieved for 1 wt% of manganese doping. [ABSTRACT FROM AUTHOR]

Highlights: [•] Contact angle were carried out for the first time for CdO thin film. [•] Effect of concentration influences the growth orientation of the CdO thin films. [•] Concentrations of Cd ions modify the physical properties of CdO thin films. [•] High Transmittance (more than 90%) was observed for CdO thin film. [Copyright &y& Elsevier]

Cadmium oxide (CdO) thin film was optimized on glass substrate at 250 °C using a chemical spray pyrolysis (CSP) technique followed by Al atoms doped into it with various wt% in order to study its influence on structural, electrical, optical, morphological and gas adsorption properties of the CdO thin films. All the films are deposited in polycrystalline cubic crystal phase is confirmed by XRD. The 90% of the visible as well as near infrared (650–850 nm) region energies is transmitted in pure and Al doped CdO films. Smooth surfaces and spherical shaped nanoparticles morphologies are conspicuous in CdO films after Al doping. The prepared CdO film is of n-type conductivity with having mobility of 64.4 cm2 V-1s-1 and carrier concentrations of 2.2 ×1020 cm-3. Importantly, the mobility increases and resistivity decreases is observed on CdO film as for Al doping level. After procuring some interesting physicochemical properties in CdO films by Al doping, trimethylamine (TMA) gas sensing analysis has been scrutinized using a simple and cost effective route. Finally, it is found that low resistive and high mobility of 1.5% Al doped CdO film exhibited pronounced sensitivity, 32.12%, is due to its higher specific surface area and as well as existence of more defective sites. [ABSTRACT FROM AUTHOR]