PREPARATION AND ELECTRICAL PROPERTIES OF LEAD-FREE Bi0.5(Na0.4K0.6)0.5TiO3 THIN FILMS

2005 ◽  
Vol 12 (03) ◽  
pp. 409-412 ◽  
Author(s):  
CHANGHONG YANG ◽  
ZHUO WANG ◽  
GUANGPENG MA ◽  
SHENGLI GU ◽  
YUGUO YANG ◽  
...  

Lead-free Bi 0.5( Na 0.4 K 0.6)0.5 TiO 3 films have been synthesized by a chemical solution deposition method and deposited on p-Si (111) substrate by spin coating. Powder of the precursor solution heated at 650°C was studied by infrared scattering spectroscopy. The structural characteristics and crystallization of the films were examined by X-ray diffraction. The surface morphology and quality were studied using atomic force microscopy. The films exhibit good insulating properties and resistance to breakdown. The clockwise hysteresis curve is referred to as polarization type switching and the memory window is about 1.5 V.

2011 ◽  
Vol 18 (03n04) ◽  
pp. 121-125 ◽  
Author(s):  
Y. L. DING ◽  
X. H. ZHANG ◽  
C. H. YANG ◽  
X. Y. ZHANG ◽  
H. L. YANG

Both ferroelectric Na0.5Bi0.5TiO3 (NBT) and K0.5Bi0.5TiO3 (KBT) are considered as the best known lead-free materials. In this experiment, we prepared NBT and KBT thin films on Pt/TiO2/SiO2/Si substrates by metalorganic solution deposition. The structural properties and surface morphologies were measured using X-ray diffraction and atomic force microscopy. The NBT and KBT films show higher leakage currents due to the oxygen vacancies in the films. The remanent polarization and coercive field of NBT (KBT) thin film are 9 (5.2) μC/cm2 and 50 (25) kV/cm at an applied electric field of 150 kV/cm. The relative dielectric constants of NBT and KBT are 340 and 316 at 1 MHz, respectively.


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.


2006 ◽  
Vol 21 (3) ◽  
pp. 767-773 ◽  
Author(s):  
M.S. Bhuiyan ◽  
M. Paranthaman ◽  
A. Goyal ◽  
L. Heatherly ◽  
D.B. Beach

Epitaxial films of rare-earth (RE = La, Ce, Eu, and Gd) tantalates, RE3TaO7 with pyrochlore structures were grown on biaxially textured nickel-3 at.% tungsten (Ni-W) substrates using chemical solution deposition (CSD) process. Precursor solution of 0.3∼0.4 M concentration of total cations were spin coated on to short samples of Ni-W substrates and the films were crystallized at 1050∼1100 °C in a gas mixture of Ar- 4% H2 for 15 to 60 min. X-ray studies show that the films of pyrochlore RE tantalate films are highly textured with cube-on-cube epitaxy. Improved texture was observed in case of lanthanum tantalate (La3TaO7) film grown on Ni-W substrates. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) investigations of RE3TaO7 films reveal a fairly dense and smooth microstructure without cracks and porosity. The rare-earth tantalate layers may be potentially used as buffer layers for YBa2Cu3O7-δ (YBCO) coated conductors.


2000 ◽  
Vol 654 ◽  
Author(s):  
P. C Joshi ◽  
M. W. Cole ◽  
C. W. Hubbard ◽  
E. Ngo

AbstractIn this paper, we report on the fabrication and characterization of pure and Al doped Ta2O5 thin films fabricated by metalorganic solution deposition (MOSD) technique. The pure and Aldoped Ta2O5 thin films were fabricated by spin-coating technique using room temperature processed carboxylate-alkoxide precursor solution. The structure of the films was analyzed by xray diffraction (XRD). The surface and cross-sectional morphology of the films were examined by field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). The electrical measurements were conducted on films in MIM configuration using Pt as the top and bottom electrode. The effects of Al concentration and the post-deposition annealing temperature on the structural, dielectric, and insulating properties were analyzed. The effects of the applied bias and the measurement temperature on the dielectric and insulating properties were also analyzed to establish the stability and reliability of Al doped Ta2O5 thin films.


Author(s):  
T. C. Marsh ◽  
J. Vesenka ◽  
E. Henderson

Atomic-Force Microscopy (AFM) has become an effective tool in the three dimensional characterization of biological systems and is capable of Angstrom sensitivity in the vertical dimension. One unresolved dilemma is that the observed height (diameter) of B-DNA being about 10Å, is less than half its x-ray diffraction value. In this paper we attempt to determine the source of this discrepancy by comparing plasmid DNA co-deposited with a novel form of DNA called “G-wires” (Figure 1). G-wires are formed by G-rich sequences. They are composed of G-4 DNA, a quadruple helical structure. X-ray data of G-4 DNA gives a diameter of 27Å, comparable to that expected for B-DNA (20 to 25Å). In the AFM these structures have a significantly greater height (av. = 22 Å) compared to double stranded (av. = 7 Å) or supercoiled B-DNA (av. = 14 Å) (Figure 2). Thus, the apparent height of nucleic acids in the AFM is dependent upon their innate structural characteristics.


2011 ◽  
Vol 15 (1) ◽  
pp. 49-55
Author(s):  
V. Dhanasekaran ◽  
T. Mahalingam ◽  
S. Rajendran ◽  
Jin Koo Rhee ◽  
D. Eapen

CuO thin films were coated on ITO substrates by an electrodeposition route through potentiostatic mode. The electrodeposited CuO thin films were characterized and the role of copper sulphate concentration on the structural, morphological and optical properties of the CuO films was studied. Film thickness was measured by a stylus profilometer and found to be in the range between 800 and 1400 nm. The structural characteristics studies were carried out using X-ray diffraction and found that the films are polycrystalline in nature with a cubic structure. The preferential orientation of CuO thin films is found to be along (111) plane. The estimated microstructural parameters revealed that the crystallite size increases whereas the number of crystallites per unit area decreases with increasing film thickness. SEM studies show that the grain sizes of CuO thin films vary between 100 and 150 nm and also morphologies revealed that the electrodeposited CuO exhibits uniformity in size and shape. The surface roughness is estimated 15 nm of the CuO film were studied by atomic force microscopy. Optical properties of the films were analyzed from absorption and transmittance studies. The optical band gap energy was determined to be 1.5 eV from absorption coefficient. The variation of refractive index (n), extinction coefficient (k), with wavelength was studied and the results are discussed.


2008 ◽  
Vol 15 (06) ◽  
pp. 799-803 ◽  
Author(s):  
XIANGYANG JING ◽  
BAIBIAO HUANG ◽  
SHUSHAN YAO ◽  
QI ZHANG ◽  
ZEYAN WANG ◽  
...  

Ce -doped Bi 2 Ti 2 O 7 thin films have been successfully prepared on P-type Si substrates by a chemical solution deposition method. The structural properties of the films were studied by X-ray diffraction. The phase of Ce -doped Bi 2 Ti 2 O 7 was more stable than that of Bi 2 Ti 2 O 7 without Ce substitution. The films exhibited good insulating properties at room temperature. The dielectric constant of the films annealed at 700°C at 100 kHz was 168 and the dissipation factor was 0.038. All these results showed that Ce -doped Bi 2 Ti 2 O 7 thin films could be used as storage capacitors in DRAM and MOS.


2004 ◽  
Vol 11 (02) ◽  
pp. 211-215
Author(s):  
CHANGHONG YANG ◽  
ZHUO WANG ◽  
XIUFENG CHENG ◽  
HONGXIA LI ◽  
JIANRU HAN ◽  
...  

A thin-film bilayer structure consisting of polycrystalline Pb 0.85 Sm 0.1 TiO 3 and preferentially (111)-oriented Bi 2 Ti 2 O 7 were prepared using the chemical solution deposition technique. Thin films were deposited by spin-coating. The structural properties of the films were examined by X-ray diffraction. The surface morphology and quality were studied by using an atomic force microscope. The films exhibit a good insulating property and resistance to breakdown. The clockwise hysteresis curve is referred to as polarization type switching, and the memory window is about 3.5 V. The accumulation capacitance and dielectric loss decrease with the increased annealing temperature. The ( Pb, Sm ) TiO 3/ Bi 2 Ti 2 O 7 films in the "on" and "off" states are relatively stable.


2010 ◽  
Vol 148-149 ◽  
pp. 1144-1147
Author(s):  
Xiang Rong Zhu ◽  
Lin Feng Lu ◽  
Hong Lie Shen

NixZn1-xFe2O4 (x=0.4, 0.6) powders are synthesized by sol-gel technique. The X-ray diffraction (XRD) measurements show their polycrystalline spinel structural characteristics. Both XRD and Atomic Force Microscopy demonstrate the samples are nanosized. At room temperature typical soft magnetism is exhibited by the samples. The reflection attenuation resulting from microwave absorption would reach to 1.9 dBm over the frequency range 6 GHz - 10 GHz when the samples are paved on a 10 cm  10 cm square aluminum plate with a thickness of about 0.35 mm.


1999 ◽  
Vol 596 ◽  
Author(s):  
E. Ching-Prado ◽  
W. Pérez ◽  
P. S. Dobalt ◽  
R. S. Katiyart ◽  
S. Tirumala ◽  
...  

AbstractThin films of ferroelectric (SrBi2Ta2O9)x(Bi3TiNbO9)1-x layered structure (for x = 0.0, 0.2, … 1.0) were prepared by a metal organic solution deposition method on Pt/TiO2/SiO2/Si substrates. Raman spectroscopy, X-ray diffraction, atomic force microscopy (AFM), and electrical characterization techniques were utilized to study the inclusion of SrBi2Ta2O9 (SBT) in the Bi3TiNbO9 (BTN) system. The Raman spectra show frequency shifts and broadening of modes as x increases from 0.0 to 0.4, which are related to the nature of Sr and Bi in the A-sites, and Ta, Ti, and Nb in the B-sites. Smooth surfaces without any cracks or defects were evidenced in each of these films by AFM. These images also indicate that the grain size in the films increases with increasing SBT content in the BTN compound. Electrical measurements show that the remanent polarization (Pr) and the coercive field (Ec) values in the x=0.0 film (2 μC/cm2 and 30 kV/cm, respectively) increase to 12.5 μC/cm2 and 125 kV/cm for x=0.6. A decrease in these parameters was found for higher compositions.


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