Sabah M. Mohammad

Influence of solution deposition rate on properties of V2O5 thin films deposited by spray pyrolysis technique

Vanadium oxide (V2O5) thin films were deposited on glass substrates by using a cost-efficient spray pyrolysis technique. The films were grown at 350° through thermal decomposition of VCl3 in deionized water with different solution spray rates. The high resolution X-ray diffraction results revealed the formation of nanocrystalline films having orthorhombic structures with preferential orientation along (101) direction. The spray rate influenced the surface morphology and crystallite size of the films. The crystallite size was found to increase whereas the micro-strain was decreased by increasing the spray deposition rates. The increase in crystallite size and decrease in the macrostrain resulted in an improvement in the films’ crystallinity. The UV-Visible spectroscopy analysis indicated that the average transmittance of all films lies in the range 75-80 %. The band gap of V2O5 film was decreased from 2.65 to 2.46 eV with increase of the spray deposition rate from 5 ml/min to 10 ml/min. first, second, and ...

Hydrothermal growth and characterization of vertically well-aligned and dense ZnO nanorods on glass and silicon using a simple optimizer system

Vertically, well-aligned and high density ZnO nanorods were successfully hydrothermally grown on glass and silicon substrates using a simple and low cost system. The mechanism of synthesis of ZnO nanorods, generated with our system under hydrothermal conditions, is investigated in this report. Field-emission scanning electron microscopy indicated that the fabricated ZnO nanorods on both substrates have hexagonal shape with diameters ranging from 20 nm to 70 nm which grew vertically from the substrate. XRD analysis confirms the formation of wurtzite ZnO phase with a preferred orientation along (002) direction perpendicular on the substrate and enhanced crystallinity. The low value of the tensile strain (0.126 %) revealed that ZnO nanorods preferred to grow along the c-axis for both substrates. Photoluminescence spectra exhibited a strong, sharp UV near band edge emission peak with narrow FWHM values for both samples.

Formation and analysis of ZnO-PAni hexagonal prisms composite prepared by chemical method

ZnO–polyaniline (PAni) nanocomposites were fabricated through a chemical method using Zinc acetate hexahydrate, ammonium hydroxide and different ratios (5, 15, 20 wt %) polyaniline. The FESEM images of the nanocomposites revealed that ZnO-PAni nanocomposites have a twin-prism structure. The XRD analysis has shown the hexagonal wurtzite structure of ZnO. Presence of P Ani did not cause any change in crystal structure of ZnO. Results of UV–Vis spectra indicate that the ZnO-PAni nanocomposites absorbed visible and ultraviolet light. This may be may be one of the interesting qualities of the prepared ZnO-PAni nanocomposites. Remarkable changes in the properties of the composites were observed, which are due to the interfacial interactions between ZnO and PAni, The interactions caused by hydrogen linkages and surface effects were observed by Raman spectrum analyses.

Growth and characterization of V2O5 nanorods deposited by spray pyrolysis at low temperatures

Vanadium pentoxide (V2O5) nanorods were deposited by spray pyrolysis on preheated glass substrates at low temperatures. The influence of substrate temperature on the crystallization of V2O5 has been investigated. X-ray diffraction analysis (XRD) revealed that the films deposited at Tsub = 300°C were orthorhombic structures with preferential along (001) direction. Formation of nanorods from substrate surface which led to the formation of films with small-sized and rod-shaped nanostructure is observed by field scanning electron microscopy. Optical transmittance in the visible range increases to reach a maximum value of about 80% for a substrate temperature of 350°C. PL spectra reveal one main broad peak centered around 540 nm with high intensity.