N. M. Abd-Alghafour

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.

INFLUENCE OF ANNEALING DURATION ON THE GROWTH OF V2O5 NANORODS SYNTHESIZED BY SPRAY PYROLYSIS TECHNIQUE

This paper deals with the investigation of annealing effects on the structural, morphological and optical properties of V2O5 nanorods (NRs) grown on the glass substrates by using chemical spray pyrolysis technique. The as-prepared samples were annealed at 500∘ for 40, 60 and 120 min in a quartz tube furnace. The high resolution X-ray diffraction (XRD) analysis revealed V2O5 NRs with preferred orientation along (001) plane. The crystallite size of the V2O5 NRs was increased by increasing the annealing duration. The morphological observations using field emission scanning electron microscope (FESEM) displayed NRs structures whose diameter and length were found to increase with increase of the annealing duration. The transmission electron microscopy (TEM) analysis confirmed the orthorhombic structures of the NRs. The AFM measurements indicated an increase of the average surface roughness by increasing the annealing time. The Raman spectroscopy revealed V–O–V phonon mode in the NRs annealed for 120 min. The optical bandgap was found in the range 2.6–2.58eV and observed to decrease with various duration annealed.

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.