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Abstract Quaternary Cu 2 ZnSnS 4 (CZTS) thin films with different S/(Cu+Zn+Sn) molar ratio have been deposited by homemade chemical spray pyrolysis unit. Secondary phase formation in CZTS thin films with respect to various S/(Cu+Zn+Sn) molar ratio was investigated. XRD and micro Raman results revealed that CZTS thin films belongs to kesterite crystal structure with a preferred orientation along (1 1 2) plane. Films deposited at x = 2, 1.72, 1.33 contain binary and ternary phases in addition to CZTS. High purity single phase CZTS was obtained at x = 0.80. The surface morphology of the films is found to be smooth. The optical absorption spectra showed that the absorption coefficient of the CZTS thin films is larger than 104 cm−1 in the visible region and the optical band gap varies from 2.05 eV to 1.45 eV. CZTS thin films were used as a photocatalyst to examine the effect of secondary phases in the decolorization of the Rhodamine B (RhB) dye under visible light. It was found that the presence of secondary phase significantly affects the photocatalytic performance of CZTS thin films. [ABSTRACT FROM AUTHOR]

Pristine and vanadium (V) doped CuInS 2 (CIS) thin films were grown on glass substrate using home-built chemical spray pyrolysis unit. The structural, morphological, optical and electrical properties of pristine and V doped CIS thin films have been systematically inspected. The scanning electron and atomic force microscopic (SEM and AFM) images show the well-interconnected CIS nanoparticles changed to nanorods like morphology with respect to V doping level and also the number density of the nanorods increases with doping level. Furthermore, the formation of CIS nanoparticles and V doped CIS nanorods are authentically confirmed by the transmission electron microscopic (TEM) images. Both pristine and V doped CIS thin films exhibit the body centered tetragonal crystal structure along with polycrystalline nature which is characterized using X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. The presence of dopant and host elements is confirmed by X-ray photoelectron and energy dispersive X-ray spectroscopic (XPS and EDX) analyses. The decreases of orbital energy gap values are observed using UV–Vis absorption spectra according to V doping level into the CIS lattice sites. A continuous suppression of defect related Cu-Au orderings are observed via Raman spectra as a function of V doping which also indicate the V doping significantly involved during deposition and improve the structural quality of the chalcopyrite CIS film. The electrical properties of CIS films transform enormously, switching from hole dominated (0.3782 S cm −1 ) p-type to electron dominated (27.16 S cm −1 ) n-type from 4 wt.% of V doping. It anticipates that this kind of self-assembled 1D CIS nanostructure will give huge interest to tune their physicochemical properties. [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]

Sparse CuInS 2 (CIS) microspheres were grown on CIS seed layer by a wet-chemical approach in which the nuclei layer was prepared by the chemical spray pyrolysis technique. Both layers have been found to be polycrystalline in nature and possess body centered tetragonal crystal structure. SEM and AFM analyses reveal that the CIS seed layer consists of high dense nanoparticles with the thickness of 0.97 μm and the average diameter of the as-grown microspheres is ∼2.1 μm. CIS microspheres may degrade the Cu–Au phase and improve the chalcopyrite phase in CIS film. The electrical properties of prepared films change tremendously, switching from low conductive (0.378 S cm −1 ) hole dominated P-type (CIS seed layer) to high conductive (7.324 S cm −1 ) electron dominated N-type (CIS microspheres). The results demonstrated that CIS microspheres exhibited good morphological and electrical properties and might have potential applications in photovoltaic technology. [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]

Abstract: Dense rutile TiO2 nanorods were grown on an anatase TiO2 seed layer by a wet-chemical approach in which the nuclei layer was prepared by the chemical spray pyrolysis technique. Structural, morphological, and optical properties of prepared samples were investigated using X-ray diffraction (XRD), micro-Raman, scanning electron microscopy (SEM), atomic force microscopy (AFM), UV–vis spectroscopy, and fluorescence spectroscopy. From XRD, a clear authentication that, the preferentially oriented (101) crystallographic planes indicate that the rutile TiO2 nanorods are standing randomly along the normal to the substrate surface. Anatase TiO2 seed layer and rutile nanorods structural phases are clearly confirmed by micro-Raman measurement. SEM and AFM studies reveal that the TiO2 seed layer consists of high density nanoparticles with the thickness of 0.15μm and the height of the as-grown nanorods is ~0.6μm. The band gap energy of the anatase TiO2 seed layer and rutile as-grown nanorods is calculated using UV–vis absorption spectra and the band gap values of seed layer and nanorods are 3.21eV and 2.95eV respectively. The crystal defects of prepared films are measured using photoluminescence spectra. [Copyright &y& Elsevier]