Dielectric Properties of Sol-Gel Derived MgAl2O4 Thin Films

2012 ◽  
Vol 151 ◽  
pp. 314-318
Author(s):  
Ching Fang Tseng ◽  
Cheng Hsing Hsu ◽  
Chun Hung Lai

This paper describes microstructure characteristics of MgAl2O4 thin films were deposited by sol-gel method with various preheating temperatures and annealing temperatures. Particular attention will be paid to the effects of a thermal treatment in air ambient on the physical properties. The annealed films were characterized using X-ray diffraction. The surface morphologies of treatment film were examined by scanning electron microscopy and atomic force microscopy. At a preheating temperature of 300oC and an annealing temperature of 700oC, the MgAl2O4 films with 9 μm thickness possess a dielectric constant of 9 at 1 kHz and a dissipation factor of 0.18 at 1 kHz.

2005 ◽  
Vol 475-479 ◽  
pp. 3693-3696
Author(s):  
Wen Xiu Cheng ◽  
Ai Li Ding ◽  
Ping Sun Qiu

Amorphous and crystalline (Zr0.8,Sn0.2)TiO4 (ZST) thin films deposited on Si(100) substrates have been prepared by a sol-gel process. The crystal structure and surface morphologies of the thin films have been studied by X-ray diffraction and atomic force microscopy. The crystalline ZST films on Si(100) substrata with a (111) orientation The refractive index n and extinction coefficient k of the amorphous and crystalline thin films were obtained by spectroscopy ellipsometry as a function of phone energy in the range from 0.7 to 5.4 eV. The absorption edges for amorphous and crystalline ZST are 3.83 and 3.51eV of indirect–transition type respectively.


2021 ◽  
Author(s):  
Taner Kutlu ◽  
Necdet H. Erdogan ◽  
Nazmi Sedefoglu ◽  
Hamide Kavak

Abstract This study reports the effect of annealing temperature on the structural, morphological, and optical properties of ZnO (Zinc Oxide) thin films deposited on a glass substrate by the sol-gel spin coating method. Those properties of ZnO were examined with UV-Vis, Fourier transform infrared (FTIR) and Raman spectroscopy, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray diffraction (XRD), before and after annealing. XRD results revealed that all the samples had a highly c-axis oriented wurtzite structure. A 1 (LO) mode in Raman spectra also confirmed the highly oriented ZnO films. Optical measurement indicated that transmittance of the films was above %85, and the optical band gap slightly decreased with the increasing annealing temperature from 350 to 550 °C. Morphological analysis displayed that increasing annealing temperature improved surface morphology and enlarged the grain size from 2-3 nm for as-deposited samples to 150 nm for annealed at 550 °C.


2019 ◽  
Vol 52 (5) ◽  
pp. 951-959
Author(s):  
Jie-Nan Shen ◽  
Yi-Bo Zeng ◽  
Ma-Hui Xu ◽  
Lin-Hui Zhu ◽  
Bao-Lin Liu ◽  
...  

The residual stresses and piezoelectric performance of ZnO thin films under different annealing parameters have been studied by X-ray diffraction and atomic force microscopy (AFM). First, ZnO thin films with a thickness of 800 nm were grown on a Pt/Ti/SiO2/Si substrate by magnetron sputtering. Second, the orthogonal experimental method was selected to study the effects of annealing temperature, annealing time and oxygen content on the residual stresses of the ZnO thin films. The residual stresses of the ZnO thin films were measured by X-ray diffraction and the sin2ψ method. Finally, the three-dimensional topography and piezoelectric performance of the ZnO thin films were measured by AFM. The results showed that the oxygen content during the annealing process has the greatest effect on the residual stress, followed by the annealing temperature and annealing time. A minimum residual stress and optimal piezoelectric performance can be realized by annealing the ZnO thin film in pure oxygen at 723 K for 30 min.


1995 ◽  
Vol 382 ◽  
Author(s):  
Martin Pehnt ◽  
Douglas L. Schulz ◽  
Calvin J. Curtis ◽  
Helio R. Moutinho ◽  
Amy Swartzlander ◽  
...  

ABSTRACTIn this article we report the first nanoparticle-derived route to smooth, dense, phase-pure CdTe thin films. Capped CdTe nanoparticles were prepared by injection of a mixture of Cd(CH3)2, (n-C8H17)3 PTe and (n-C8H17)3P into (n-C8H17)3PO at elevated temperatures. The resultant nanoparticles 32-45 Å in diameter were characterized by x-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy, thermogravimetric analysis and energy dispersive x-ray spectroscopy. CdTe thin film deposition was accomplished by dissolving CdTe nanoparticles in butanol and then spraying the solution onto SnO2-coated glass substrates at variable susceptor temperatures. Smooth and dense CdTe thin films were obtained using growth temperatures approximately 200 °C less than conventional spray pyrolysis approaches. CdTe films were characterized by x-ray diffraction, UV-Vis spectroscopy, atomic force microscopy, and Auger electron spectroscopy. An increase in crystallinity and average grain size as determined by x-ray diffraction was noted as growth temperature was increased from 240 to 300 °C. This temperature dependence of film grain size was further confirmed by atomic force microscopy with no remnant nanocrystalline morphological features detected. UV-Vis characterization of the CdTe thin films revealed a gradual decrease of the band gap (i.e., elimination of nanocrystalline CdTe phase) as the growth temperature was increased with bulk CdTe optical properties observed for films grown at 300 °C.


Cerâmica ◽  
2002 ◽  
Vol 48 (305) ◽  
pp. 38-42 ◽  
Author(s):  
M. I. B. Bernardi ◽  
E. J. H. Lee ◽  
P. N. Lisboa-Filho ◽  
E. R. Leite ◽  
E. Longo ◽  
...  

The synthesis of TiO2 thin films was carried out by the Organometallic Chemical Vapor Deposition (MOCVD) method. The influence of deposition parameters used during growth on the final structural characteristics was studied. A combination of the following experimental parameters was studied: temperature of the organometallic bath, deposition time, and temperature and substrate type. The high influence of those parameters on the final thin film microstructure was analyzed by scanning electron microscopy with electron dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction.


2019 ◽  
Vol 13 (26) ◽  
pp. 171-177
Author(s):  
Ban M. Al-Shabander

Titanium dioxide nanorods have been prepared by sol-gel templatemethod. The structural and surface morphology of the TiO2 nanorods wasinvestigated by X-ray diffraction (XRD) and atomic force microscopy(AFM), it was found that the nanorods produced were anatase TiO2 phase.The photocatalytic activity of the TiO2 nanorods was evaluated by thephoto degradation of methyl orange (MO). The relatively higherdegradation efficiency for MO (D%=78.2) was obtained after 6h of exposedto UV irradiation.


2016 ◽  
Vol 689 ◽  
pp. 55-59
Author(s):  
Serge Zhuiykov

Electrical properties and morphology of orthorhombic β–WO3 nano-flakes with thickness of ~7-9 nm were investigated at the nanoscale using energy dispersive X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNATM). CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nano-flakes synthesized via a two-step sol-gel-exfoliation method. It was determined that β–WO3 nano-flakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro- and nano-structured WO3 synthesized at alternative temperatures.


1999 ◽  
Vol 597 ◽  
Author(s):  
M. Siegert ◽  
Judit G. Lisoni ◽  
C. H. Lei ◽  
A. Eckau ◽  
W. Zander ◽  
...  

AbstractIn the process of developing thin film electro-optical waveguides we investigated the influence of different substrates on the optical and structural properties of epitaxial BaTiO3 thin films. These films are grown by on-axis pulsed laser deposition (PLD) on MgO(100), MgAl2O4(100), SrTiO3(100) and MgO buffered A12O3(1102) substrates. The waveguide losses and the refractive indices were measured with a prism coupling setup. The optical data are correlated to the results of Rutherford backscattering spectrometry/ion channeling (RBS/C). X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). BaTiO3 films on MgO(100) substrates show planar waveguide losses of 3 dB/cm and ridge waveguide losses of 5 dB/cm at a wavelength of 633 nm.


2003 ◽  
Vol 780 ◽  
Author(s):  
C.Z. Dinu ◽  
R. Tanasa ◽  
V.C. Dinca ◽  
A. Barbalat ◽  
C. Grigoriu ◽  
...  

AbstractPulsed Laser Deposition method (PLD) was used to grow nitinol (NiTi) thin films with goal of investigating their biocompatibility. High purity Ni and Ti targets were alternatively ablated in vacuum with a laser beam (λ=355 nm, 10 Hz) and the material was collected on room temperature Ti substrates. X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and atomic force microscopy analyses have been performed to investigate the chemical composition, crystalline structure and surface morphology of the NiTi films. The nitinol layers biocompatibility has been tested using as a metric the extent to whichthe cells adhereduring the culture period on the surface of NiTi layers deposited on Ti substrates. Vero and fibroblast cell lines dispersed into MEM (Eagle) solution containing 8% fetal bovine serum, at 37° C, were used for tests. Preliminary studies indicate that the interaction at the interface is specifically controlled by the surface morphology, (especially by surface roughness), and by the chemical state of the surface. Cell behavior after contact with NiTi/Ti structure for different intervals (18, 22 and 25 days for the Vero cells, and after 10 and 25 days for fibroblasts) supports the conclusion that NiTi is a very good candidate as a biocompatible material.


e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Guido Scavia ◽  
William Porzio ◽  
Silvia Destri ◽  
Alberto Giacometti Schieroni ◽  
Fabio Bertini

AbstractThe morphology and structure of the overlying poly(3-hexylthiophene) (P3HT) layer onto differently silanized silicon oxide has been studied by Atomic Force Microscopy (AFM) and X-Ray Diffraction (XRD) techniques. By increasing the silanizer alkyl chain length, the layer morphology evolves from a filament like to globular needle like as a consequence of the different SAM organization, while the P3HT conformation remains edge-on. For each case the effect of the annealing temperature has been studied. For all the cases a particular attention has been paid to the first thin layers close to the interface P3HT/SiOx. The effect of a polar substituent and presence of aromatic ring has been also studied.


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