Application of Vogel-Tamman-Fulcher (VTF) model to polythiophene composite thin films

2012 ◽  
Vol 32 (2) ◽  
Author(s):  
Dhananjay P. Deshmukh ◽  
Praful D. Shirbhate ◽  
Sangita S. Yawale ◽  
Shrikrishna P. Yawale
Keyword(s):  
Thin Films ◽  
Polymer Composite ◽  
Ionic Conduction ◽  
Segmental Motion ◽  
X Ray Diffraction ◽  
Iodine Doping ◽  
Arrhenius Behavior ◽  
Ionic Charge ◽  
Dta Studies

Abstract Synthesis of polymer composites poly (vinyl acetate) (PVAc) and polythiophene (PTh) was done by chemical oxidative method using FeCl3oxidant in methanol. Thin films with PTh-PVAc polymer composite were prepared for 5.5, 10.4, 14.9, 18.9 and 22.5 wt% of iodine as a dopant. Direct current (DC) conductivity as a function of temperature (313–363 K) was measured by the two probe method. Characterization of the sample was done via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG)/differential thermal analysis (DTA). The maximum value for DC electrical conductivity was found for 10.4 wt% (σ=9.78×10-10S cm-1). The decrease in conductivity for greater iodine concentrations may be due to reduced segmental motion. The temperature dependence conductivity shows percolative behavior and a clear cross over from Vogel-Tamman-Fulcher (VTF) to Arrhenius behavior. Ionic conduction decreased with increase in the concentration of iodine, which shows ionic charge transport. XRD of the samples showed an amorphous nature. FTIR spectra showed absorption in the range 550–3600 cm-1, which indicates various bands involved in the PTh-PVAc polymer composite with iodine doping. From TG/DTA studies, it was observed that all the samples with a different wt% of iodine showed degradation in a range 75–81% when heated up to 888 K.

Characterization of SrBi2Nb2O9 Thin Films Prepared by Sol Gel Technique

1996 ◽  
Vol 459 ◽  
Author(s):  
E. Ching-Prado ◽  
W. Pérez ◽  
A. Reynés-Figueroa ◽  
R. S. Katiyar ◽  
D. Ravichandran ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Band ◽  
Sol Gel ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Gel Technique ◽  
High Degree ◽  
First Time

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.

The Ferroelectric and Electrical Properties of CaBi4Ti4O15 Thin Films Prepared by Sol-Gel Technology

2011 ◽  
Vol 239-242 ◽  
pp. 891-894 ◽  
Author(s):  
Tsung Fu Chien ◽  
Jen Hwan Tsai ◽  
Kai Huang Chen ◽  
Chien Min Cheng ◽  
Chia Lin Wu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Sol Gel ◽  
Morphological Characterization ◽  
Experimental Result ◽  
X Ray Diffraction ◽  
Solution Deposition ◽  
Capacitance Voltage ◽  
Preferential Crystal Orientation

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

Structural and Optical Characterization of Zinc Telluride Thin Films

2013 ◽  
Vol 665 ◽  
pp. 254-262 ◽  
Author(s):  
J.R. Rathod ◽  
Haresh S. Patel ◽  
K.D. Patel ◽  
V.M. Pathak
Keyword(s):  
Thin Films ◽  
Extinction Coefficient ◽  
Nir Spectroscopy ◽  
Optical Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Evaporation Technique ◽  
Film Form ◽  
Znte Thin Films

Group II-VI compounds have been investigated largely in last two decades due to their interesting optoelectronic properties. ZnTe, a member of this family, possesses a bandgap around 2.26eV. This material is now a day investigated in thin film form due to its potential towards various viable applications. In this paper, the authors report their investigations on the preparation of ZnTe thin films using vacuum evaporation technique and their structural and optical characterizations. The structural characterization, carried out using an X-ray diffraction (XRD) technique shows that ZnTe used in present case possesses a cubic structure. Using the same data, the micro strain and dislocation density were evaluated and found to be around 1.465×10-3lines-m2and 1.639×1015lines/m2respecctively. The optical characterization carried out in UV-VIS-NIR region reveals the fact that band gap of ZnTe is around 2.2eV in present case. In addition to this, it was observed that the value of bandgap decreases as the thickness of films increases. The direct transitions of the carries are involved in ZnTe. Using the data of UV-VIS-NIR spectroscopy, the transmission coefficient and extinction coefficient were also calculated for ZnTe thin films. Besides, the variation of extinction coefficient with wavelength has also been discussed here.

scholarly journals Characterization of superconducting oxide thin films by X-ray diffraction.

1990 ◽  
Vol 37 (1) ◽  
pp. 141-144
Author(s):  
Tsunekazu Iwata ◽  
Akihiko Yamaji ◽  
Youichi Enomoto
Keyword(s):  
Thin Films ◽  
X Ray Diffraction ◽  
Oxide Thin Films ◽  
X Ray

Application of Aluminum Nitride Thin Film for Micromachined Ultrasonic Transducers

2005 ◽  
Vol 892 ◽  
Author(s):  
Qianghua Wang ◽  
Jianzeng Xu ◽  
Changhe Huang ◽  
Gregory W Auner
Keyword(s):  
Thin Films ◽  
Aluminum Nitride ◽  
Ultrasonic Transducers ◽  
X Ray Diffraction ◽  
Effective Coupling ◽  
Resonant Frequencies ◽  
X Ray ◽  
Coupling Factors ◽  
Sandwiched Structure

AbstractThis paper reports the fabrication and characterization of micromachined ultrasonic transducers (MUT) based on piezoelectric aluminum nitride (AlN) thin films. The MUT device is composed of an Al/AlN/Al sandwiched structure overlaid on top of a silicon (Si) diaphragm. X-ray diffraction (XRD) scan shows that highly c-axis oriented AlN (002) thin films have been grown on Al/Si(100) substrates. Electrical impedance of the MUT devices is analyzed as a function of frequency. The fundamental resonant frequencies of the devices are found in the range of 65-70 kHz, which are in approximation to the theoretical calculation. The effective coupling factors of the devices are also derived as 0.18.

scholarly journals Characterization of Electrodeposited Cadmium Selenide Thin Films

2012 ◽  
Vol 60 (1) ◽  
pp. 137-140 ◽  
Author(s):  
RI Chowdhury ◽  
MS Islam ◽  
F Sabeth ◽  
G Mustafa ◽  
SFU Farhad ◽  
...  
Keyword(s):  
Thin Films ◽  
Cadmium Selenide ◽  
Low Cost ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Cdse Film ◽  
Cell Structures ◽  
Deposited Film ◽  
Deposited Films

Cadmium selenide (CdSe) thin films have been deposited on glass/conducting glass substrates using low-cost electrodeposition method. X-ray diffraction (XRD) technique has been used to identify the phases present in the deposited films and observed that the deposited films are mainly consisting of CdSe phases. The photoelectrochemical (PEC) cell measurements indicate that the CdSe films are n-type in electrical conduction, and optical absorption measurements show that the bandgap for as-deposited film is estimated to be 2.1 eV. Upon heat treatment at 723 K for 30 min in air the band gap of CdSe film is decreased to 1.8 eV. The surface morphology of the deposited films has been characterized using scanning electron microscopy (SEM) and observed that very homogeneous and uniform CdSe film is grown onto FTO/glass substrate. The aim of this work is to use n-type CdSe window materials in CdTe based solar cell structures. The results will be presented in this paper in the light of observed data.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10352  Dhaka Univ. J. Sci. 60(1): 137-140 2012 (January)

Preparation and Characterization of Zn1-XMnxO Thin Films on SiO2 Substrates

2012 ◽  
Vol 560-561 ◽  
pp. 820-824
Author(s):  
Yue Zhi Zhao ◽  
Fei Xiong ◽  
Guo Mian Gao ◽  
Shi Jing Ding
Keyword(s):  
Thin Films ◽  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Flat Surfaces ◽  
Atomic Force ◽  
Mn Content ◽  
Doped Zno ◽  
Mn Doped

Mn-doped ZnO thin films were prepared on SiO2substrates by using a radio-frequency(rf) magnetron sputtering in order to investigate structure and optical proprieties of the films. X-ray diffraction (XRD), Atomic force microscope (AFM) and UV-VIS spectrophotometry were employed to characterize the Mn-doped ZnO films. The results showed that the shape of the XRD spectrum was remarkably similar to that of the un-doped ZnO film; the film had mainly (002) peak, and indicate that the structure of the films was not disturbed by Mn-doped. The film had rather flat surfaces with the peak-to-tail roughness of about 25nm. Mn-doping changed the band gap of the films, which increased with the increase of the Mn content.

Sol-gel synthesis and characterization of Ag nanoparticles in ZrO2 thin films

2009 ◽  
Vol 24 (8) ◽  
pp. 2541-2546 ◽  
Author(s):  
Eisuke Yokoyama ◽  
Hironobu Sakata ◽  
Moriaki Wakaki
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Composite Films ◽  
Dip Coating ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Silver Surface ◽  
Molar Ratios ◽  
Sol Gel Synthesis

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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