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Undoped and doped Cadmium oxide (CdO) films with different Mn concentrations were prepared on glass substrates by the successive ionic layer adsorption and reaction method and annealed at two different temperatures. Structural, morphological and optical conditions were performed by XRD, scanning electron microscope (SEM) and UV–vis spectrum measurements. The deposited films were dense and they adhere well to the glass substrates. From the SEM photographs, it was seen that Mn doping concentration and annealing process affect the morphologies of the nanostructures. It was found that the growth process modifies the microstructures of the CdO films. XRD results and UV–vis analysis reveal that the crystal structure and optical band gap of the films could be adjusted by varying the Mn concentration and annealing temperature. The results also indicate that there is a direct dependence of the physical and optical properties of the metal oxide films on doping concentration and annealing process. [ABSTRACT FROM AUTHOR]

This paper describes a simple, low-temperature and cost-effective liquid-phase method to synthesize homogenous plate-like CuO nanostructures and their sensitivity to humidity. Scanning electron microscopy illustrated that the synthesized CuO nanoplates have thicknesses of ~100 nm. X-ray diffraction measurements showed that the CuO nanostructures have high crystallinity with monoclinic crystal structure preferentially inanddirections. From the temperature-dependant dark electrical resistivity measurements, the ionization energies of the impurity levels and thermal band gap energies of the films are found as 0.30, 0.32 and 1.37, 1.39 for as-synthesized and annealed films, respectively. Gas sensing characteristics of the films were investigated for different concentrations of humidity, isopropyl alcohol, methanol, ethanol, chloroform and acetone vapours. It was found that the sensor is sensitive to humidity but not to the other volatile organic compounds. [ABSTRACT FROM AUTHOR]

Abstract: Un-doped and Co-doped CdO nanostructures were deposited on glass substrates by successive ionic layer adsorption and reaction (SILAR) method and annealed at 300 and 400°C. Morphological, structural and optical properties of the films were investigated by scanning electron microscope (SEM), X-ray diffractometer (XRD) and ultra violet-vis (UV–vis) spectrophotometry. The analyzed results indicate that Co-doping concentration and annealing temperature affect the properties of nanostructure cadmium oxide (CdO) films. XRD results showed that all of the films are polycrystalline cubic CdO with good crystallinity levels. With UV–vis. analysis at the room temperature it was found that the doping and annealing temperature changed optical properties of CdO films. [Copyright &y& Elsevier]

Highlights: [•] The first study analyzing the impact of coumarin content on CuO nanostructures. [•] Optical bandgap can be manipulated by adjusting the coumarin concentration. [•] Crystallite size can be manipulated by adjusting the coumarin concentration. [•] Transmission characteristics can be tuned accordingly by coumarin concentration. [Copyright &y& Elsevier]

In this paper, undoped and tin-doped ZnO nanostructures were grown onto non-conductive substrates by a simple solution method. Structural, morphological, optical and electrical properties of the structures were investigated with respect to tin concentration. From XRD studies, all the ZnO nanostructures were found as hexagonal wurtzite type structures growing preponderantly oriented with c-axis normal to the substrate. An increase in tin content resulted in a decrease in grain size, whereas the dislocation density increases. SEM observations indicated that all the structures were textured throughout the substrates without any cracks or pores. The influence of incorporation of tin on surface morphology of the samples was clearly seen. Average diameter of the nanostructures decreased with increasing tin content. Absorption spectra of the structures revealed that the band gap of the films increases with increasing tin concentration. It is found that the tin-doped samples have higher average transmittance than the undoped one. The 1 % tin-doped sample exhibited ∼80 % average transparency, which was the best transparency among the doped samples. Electrical measurements showed that resistivity of the structures increased with increasing dopant concentration. This increasing was attributed due to a decrease in carrier concentration caused by carrier traps at the grain boundaries. [ABSTRACT FROM AUTHOR]

Abstract: Highly c-axis oriented ZnO films were deposited on seeded glass substrates. Successive ionic layer adsorption and reaction (SILAR) method and chemical bath deposition (CBD) method were used to obtain seed layers and ZnO films. To see the effects of seed layer and deposition time, structural (e.g. grain size, microstrain and dislocation density), morphological, and electrical (e.g. resistivity, activation energy) properties of the films were investigated by scanning electron microscopy, X-ray diffraction, and four point probe method. From the SEM images, resultant structures were found as well defined nanorods nearly perpendicular to the substrate surfaces and densely cover the substrates. The XRD patterns showed that ZnO films have hexagonal wurtzite structure with a preferred c-axis orientation along (002) plane. C-axis orientation was also supported by texture coefficient calculations. The lattice parameters of the structures were determined as a = 3.2268 Å, b = 5.2745 Å, α = β = 90° and γ = 120°. From the XRD patterns, it was revealed that, microstrain and dislocation density values of the structures decreased whereas grain size increased. This was attributed to enhancement occurred in lattice structure of the ZnO films. Activation energy values of the films were found in between 0.12 and 0.15 eV from the dark electrical resistivity-temperature characteristics in a temperature range of 300–500 K. [Copyright &y& Elsevier]

This novel study reports the behaviour of coumarin during the ZnO chemical bath deposition (CBD) process. Scanning electron microscopy studies revealed that grain sizes of the ZnO nanostructures get smaller and become more uniform in size with increasing coumarin content. Length-to-diameter ratio of the structures increased with the incorporation of coumarin. From the X-Ray diffraction results, with increasing coumarin content, significant decrease in grain sizes was determined. It was found that resistivity values of the structures increased with increasing coumarin content. This increase is attributed with a decrease in carrier concentration originated by carrier traps at the grain boundaries. Through slopes of versus curves, impurity level ionization energy values were calculated as 0.16, 0.06 eV; 0.11, 0.02 eV; and 0.08, 0.06 eV for the structure growth in the solutions containing 0, 1 and 5 at.% coumarin, respectively. [ABSTRACT FROM PUBLISHER]

Abstract: Five series of pure and tin-doped CdO films have been grown on amorphous glass substrates by the successive ionic layer adsorption and reaction (SILAR) method. The film׳s structural, morphological and optical properties have been investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and UV–vis spectrophotometer. XRD results showed that all of the films are polycrystalline cubic CdO. Doping of tin enhances the film׳s (111) preferred orientation and causes slight shift in the (111) Bragg angle towards higher value. From the FESEM images, it was seen that tin-doping concentration affects the shapes of the nanostructures. It was found that the tin-doping concentration modify the microstructures. With UV–vis analysis at the room temperature it was seen that the optical band gap and transmission properties of the films change with increasing tin concentration in the growth bath. [Copyright &y& Elsevier]

Highlights: [•] The crystallite size of pure CdO was about 18nm. [•] Ba doped CdO films show a shift of Eg to higher energies. [•] The physical properties can be controlled by dopant concentrations. [ABSTRACT FROM AUTHOR]