Growth of nanotubes in sol-gel-derived V2O5 powders and films prepared under acidic conditions

2009 ◽  
Vol 24 (2) ◽  
pp. 475-481 ◽  
Author(s):  
R. Ceccato ◽  
S. Dirè ◽  
T. Barone ◽  
G. De Santo ◽  
E. Cazzanelli

The structural evolution with temperature of some V2O5 gels and thin films is presented, and the role of the hydrolysis conditions is investigated. Several techniques, i.e., x-ray diffraction, differential thermal analysis, infrared, and temperature-dependent Raman spectroscopy, have been used to follow the thermal behavior of the samples. When the bulk xerogels begin to change from a nanocrystalline phase to the orthorhombic α-V2O5, in the temperature range 280 to 300 °C, a growth of vanadium oxide nanotubes also occurs, while at higher temperatures the crystallization into the α phase prevails. A slightly different evolution is observed for heat treated thin films, which show a structure containing polyvanadate chains near room temperature. They also present a growth of nanotubes for intermediate temperatures and a complete crystallization into the α phase when the temperature is further increased.

1994 ◽  
Vol 9 (2) ◽  
pp. 420-425 ◽  
Author(s):  
Dae Sung Yoon ◽  
Chang Jung Kim ◽  
Joon Sung Lee ◽  
Won Jong Lee ◽  
Kwangsoo No

Epitaxial lead lanthanum zirconate titanate [PLZT(9/50/50)] thin films were fabricated on various single crystal substrates using the spin coating of metallo-organic solutions. The films were heat-treated at 700 °C for 1 h using the direct insertion method. The films were epitaxially grown with (100), (100), and (110) being parallel to the SrTiO3(100), the MgO(100), and the sapphire (0112) substrates, respectively. The epitaxy of the films was investigated using x-ray diffraction, pole figures, rocking curves, and scanning electron microscopy.


2019 ◽  
Vol 74 (7) ◽  
pp. 635-642
Author(s):  
Zohra N. Kayani ◽  
Mehawish Saleem ◽  
Saira Riaz ◽  
Shahzad Naseem ◽  
Farhat Saleemi

AbstractTitanium dioxide (TiO2) thin films were deposited on CR-39 by a sol-gel dip coating route with different withdrawal speeds ranging from 250 to 350 mm/s. The TiO2 thin films were characterised by x-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, ellipsometry, and ultraviolet (UV)-visible (VIS)-near infrared (NIR) spectro-photometry. The role of withdrawal speed on the thickness of thin films to tailor properties of TiO2 thin films was studied. The XRD results revealed that all the films are amorphous in nature. TiO2 thin films deposited at different withdrawal speeds exhibit a decrease in transmission with an increase in speed. The direct optical band gap of the films has been estimated to be in the range 3.48–3.00 eV by UV-VIS-NIR spectro-photometry and 3.52–3.38 eV by ellipsometry. TiO2 is a potential prospect in microelectronic applications and can serve as an absorber layer for photovoltaic devices. Surface morphology is granular with an increase in grain size and an increase in withdrawal speed.


1994 ◽  
Vol 343 ◽  
Author(s):  
Dae Sung Yoon ◽  
Chang Jung Kim ◽  
Joon Sung Lee ◽  
Chaun Gi Choi ◽  
Won Jong Lee ◽  
...  

ABSTRACTHighly preferentially oriented lead lathanum zirconate titanate(PLZT) thin films were fabricated on various substrates using the spin coating of metal organic solutions having the composition of (9/50/50) and (10/0/100). The substrates used in this study were SrTiO3(100), MgO(100), r-plane sapphire, PLT-coated glass, and Pt/Ti/MgO substrates. The films were heat-treated at 600°C and 700°C using the direct insertion method. The phases and the orientation of the PLZT thin films were examined using X-ray diffraction(XRD). Pole figure and X-ray rocking curves were measured to study the film orientation. The films were grown with (100), (110), and (001) plane being parallel to the surfaces of SrTiO3, sapphire, and Pt/Ti/MgO, respectively. The dielectric and optical properties of both the oriented films and the noncrystalline films were measured and discussed.


2006 ◽  
Vol 514-516 ◽  
pp. 1155-1160 ◽  
Author(s):  
Talaat Moussa Hammad

Sol gel indium tin oxide thin films (In: Sn = 90:10) were prepared by the sol-gel dipcoating process on silicon buffer substrate. The precursor solution was prepared by mixing SnCl2.2H2O and InCl3 dissolved in ethanol and acetic acid. The crystalline structure and grain orientation of ITO films were determined by X-ray diffraction. The surface morphology of the films was characterized by scanning electron microscope (SEM). Optical transmission and reflectance spectra of the films were analyzed by using a UV-visible spectrophotometer. The transport properties of majority charge carriers for these films were studied by Hall measurement. ITO thin film with electrical resistivity of 7.6 ×10-3 3.cm, Hall mobility of approximately 2 cm2(Vs)-1 and free carrier concentration of approximately 4.2 ×1020 cm-3 are obtained for films 100 nm thick films. The I-V curve measurement showed typical I-V characteristic behavior of sol gel ITO thin films.


1996 ◽  
Vol 459 ◽  
Author(s):  
E. Ching-Prado ◽  
W. Pérez ◽  
A. Reynés-Figueroa ◽  
R. S. Katiyar ◽  
D. Ravichandran ◽  
...  

ABSTRACTThin films of SrBi2Nb2O9 (SBN) with thicknesses of 0.1, 0.2, and 0.4 μ were grown by Sol-gel technique on silicon, and annealed at 650°C. The SBN films were investigated by Raman scatering for the first time. Raman spectra in some of the samples present bands around 60, 167, 196, 222, 302, 451, 560, 771, 837, and 863 cm−1, which correspond to the SBN formation. The study indicates that the films are inhomogeneous, and only in samples with thicknesses 0.4 μ the SBN material was found in some places. The prominent Raman band around 870 cm−1, which is the A1g mode of the orthorhombic symmetry, is assigned to the symmetric stretching of the NbO6 octahedrals. The frequency of this band is found to shift in different places in the same sample, as well as from sample to sample. The frequency shifts and the width of the Raman bands are discussed in term of ions in non-equilibrium positions. FT-IR spectra reveal a sharp peak at 1260 cm−1, and two broad bands around 995 and 772 cm−1. The bandwidths of the latter two bands are believed to be associated with the presence of a high degree of defects in the films. The experimental results of the SBN films are compared with those obtained in SBT (T=Ta) films. X-ray diffraction and SEM techniques are also used for the structural characterization.


2002 ◽  
Vol 737 ◽  
Author(s):  
R.E. Melgarejo ◽  
M.S. Tomar ◽  
A. Hidalgo ◽  
R.S. Katiyar

ABSTRACTNd substituted bismuth titanate Bi4-xNdxTi3O12 were synthesized by sol-gel process and thin films were deposited on Pt substrate (Pt/TiO2/SiO2/Si) by spin coating. Thin films, characterized by X-ray diffraction and Raman spectroscopy, shows complete solid solution up to the composition x < 1. Initial results indicate that the ferroelectric polarization increases with increasing Nd content in the film with 2Pr = 50μC/cm2 for x = 0.46, which may have application in non-volatile ferroelectric memory devices.


2011 ◽  
Vol 239-242 ◽  
pp. 891-894 ◽  
Author(s):  
Tsung Fu Chien ◽  
Jen Hwan Tsai ◽  
Kai Huang Chen ◽  
Chien Min Cheng ◽  
Chia Lin Wu

In this study, thin films of CaBi4Ti4O15with preferential crystal orientation were prepared by the chemical solution deposition (CSD) technique on a SiO2/Si substrate. The films consisted of a crystalline phase of bismuth-layer-structured dielectric. The as-deposited CaBi4Ti4O15thin films were crystallized in a conventional furnace annealing (RTA) under the temperature of 700 to 800°C for 1min. Structural and morphological characterization of the CBT thin films were investigated by X-ray diffraction (XRD) and field-emission scanning electron microscope (FE-SEM). The impedance analyzer HP4294A and HP4156C semiconductor parameters analyzer were used to measurement capacitance voltage (C-V) characteristics and leakage current density of electric field (J-E) characteristics by metal-ferroelectric-insulator- semiconductor (MFIS) structure. By the experimental result the CBT thin film in electrical field 20V, annealing temperature in 750°C the CBT thin film leaks the electric current is 1.88x10-7A/cm2and the memory window is 1.2V. In addition, we found the strongest (119) peak of as-deposited thin films as the annealed temperature of 750°C


2010 ◽  
Vol 93-94 ◽  
pp. 231-234
Author(s):  
B. Hongthong ◽  
Satreerat K. Hodak ◽  
Sukkaneste Tungasmita

Strontium substituted hydroxyapatite(SrHAp) were fabricated both in the form of powder as reference and thin film by using inorganic precursor reaction. The sol-gel process has been used for the deposition of SrHAp layer on stainless steal 316L substrate by spin coating technique, after that the films were annealed in air at various temperatures. The chemical composition of SrHAp is represented (SrxCa1-x)5(PO4)3OH, where x is equal to 0, 0.5 and 1.0. Investigations of the phase structure of SrHAp were carried out by using X-ray diffraction technique (XRD). The results showed that strontium is incorporated into hydroxyapatite where its substitution for calcium increases in the lattice parameters, and Sr3(PO4)2 can be detected at 900°C. The SEM micrographs showed that SrHAp films exhibited porous structure before develop to a cross-linking structure.


2020 ◽  
Vol sceeer (3d) ◽  
pp. 93-98
Author(s):  
Marwan Younus ◽  
Muayad Ahmed ◽  
Ghazwan Ali

In this study, Dielectric Barrier Discharge plasma irradiation (DBD) is applied to treatment and improve the properties of the ZnO thin film deposited on the glass substrate as a sensor for glucose detection. The ZnO is prepared via a sol-gel method in this work. ZnO is irradiated by the DBD high voltage plasma to improve of its sensitivity. The optical properties, roughness and surface morphology of the waveguide coated ZnO thin films before and after DBD plasma irradiation are studied in this work. The results showed a significant improvement in the performance of the sensor in the detection of concentrations of glucose solution after plasma irradiation. Where the largest value in sensitivity was equal to 62.7 when the distance between electrodes was 5 cm compared to the sensitivity before irradiation, which was equal to 92. The high response showed in results demonstrating that the fabricated waveguide coated ZnO after plasma irradiation has the excellent potential application as a sensor to detect small concentration of glucose solution.


2009 ◽  
Vol 24 (8) ◽  
pp. 2541-2546 ◽  
Author(s):  
Eisuke Yokoyama ◽  
Hironobu Sakata ◽  
Moriaki Wakaki

ZrO2 thin films containing silver nanoparticles were prepared using the sol-gel method with Ag to Zr molar ratios [Ag]/[Zr] = 0.11, 0.25, 0.43, 0.67, 1.00, 1.50, and 2.33. After dip coating on glass substrate, coated films were annealed at 200 and 300 °C in air. X-ray diffraction peaks corresponding to crystalline Ag were observed, but a specific peak corresponding to ZrO2 was not observed. At the molar ratio [Ag]/[Zr] = 0.25, the particle size of Ag distributed broadly centered at 17 nm for an annealing temperature of 200 °C and at 25 nm for 300 °C. The films annealed in air at 200 °C showed an absorption band centered at 450 nm because of the silver surface plasmon resonance, whereas films heated at 300 °C in air caused a red shift of the absorption to 500 nm. The absorption peak was analyzed using the effective dielectric function of Ag-ZrO2 composite films modeled with the Maxwell-Garnett expression.


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