PREPARATION AND FERROELECTRIC PROPERTIES OF LEAD-FREE A0.5Bi0.5TiO3 (A = Na OR K) THIN FILMS

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.

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.


1998 ◽  
Vol 13 (5) ◽  
pp. 1318-1326 ◽  
Author(s):  
P. C. Liao ◽  
W. S. Ho ◽  
Y. S. Huang ◽  
K. K. Tiong

Iridium dioxide (IrO2) thin films, deposited on Si substrates by reactive rf sputtering method under various conditions, were characterized by atomic force microscopy (AFM), x-ray diffraction (XRD), electrical-conductivity, spectrophotometry, ellipsometry and Raman scattering measurements. The average grain sizes of the films were estimated by AFM. A grain boundary scattering model was used to fit the relation between the average grain size and electrical resistivity. The optical and dielectric constants were determined by the ellipsometry measurements. The results of the electrical and optical studies show a metallic character of the films deposited at higher temperatures. The results of XRD and Raman scattering indicate that the IrO2 films deposited at temperatures higher than 300 °C show the presence of (200) texture.


2021 ◽  
Vol 21 (4) ◽  
pp. 2681-2686
Author(s):  
Nguyen Ngoc Minh ◽  
Bui Van Dan ◽  
Nguyen Duc Minh ◽  
Guus Rijnders ◽  
Ngo Duc Quan

Lead-free Bi0.5K0.5TiO3 (BKT) ferroelectric films were synthesized on Pt/Ti/SiO2/Si substrates via the chemical solution deposition. The influence of the excess potassium on the microstructures and the ferroelectric properties of the films was investigated in detail. The results showed that the BKT films have reached the well-crystallized state in the single-phase perovskite structure with 20 mol.% excess amount of potassium. For this film, the ferroelectric properties of the films were significantly enhanced. The remnant polarization (Pr) and maximum polarization (Pm) reached the highest values of 9.4 μC/cm2 and 32.2 μC/cm2, respectively, under the electric field of 400 kV/cm.


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.


2012 ◽  
Vol 545 ◽  
pp. 290-293
Author(s):  
Maryam Amirhoseiny ◽  
Hassan Zainuriah ◽  
Ng Shashiong ◽  
Mohd Anas Ahmad

We have studied the effects of deposition conditions on the crystal structure of InN films deposited on Si substrate. InN thin films have been deposited on Si(100) substrates by reactive radio frequency (RF) magnetron sputtering method with pure In target at room temperature. The nitrogen gas pressure, applied RF power and the distance between target and substrate were 2×10-2 Torr, 60 W and 8 cm, respectively. The effects of the Ar–N2 sputtering gas mixture on the structural properties of the films were investigated by using scanning electron microscope, energy-dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction techniques.


2013 ◽  
Vol 446-447 ◽  
pp. 306-311 ◽  
Author(s):  
Sudhanshu Dwivedi ◽  
Somnath Biswas

Mixed phase TiO2 thin films of rutile and anatase type crystal orientations were deposited on Si substrates by pulsed laser deposition (PLD) technique. When annealed at 800°C at 1 mbar oxygen pressure for 3 h, the deposited films transform into a single phase of rutile type. Structural and morphological studies of the as-deposited and annealed films were performed with X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), Raman spectroscopy, and atomic force microscopy (AFM). Photoluminescence (PL) spectroscopy was used for optical characterization of the annealed thin films.


2012 ◽  
Vol 512-515 ◽  
pp. 368-371
Author(s):  
Yan Chao Hou ◽  
Jian Feng Huang ◽  
Li Yun Cao ◽  
Jian Peng Wu

Sm2S3 thin films were prepared on Si (100) substrates by liquid phase self–assemble method. The influences of solution pH value on the phases, surface morphologies and optical properties of the as deposited films were investigated. The as–deposited Sm2S3 thin films were characterized by X–ray diffraction (XRD), atomic force microscopy (AFM) and ultraviolet-visible (UV–Vis). Results indicate that Sm2S3 thin film with oriented growth along (105) direction can be obtained at pH value of 3.0, deposition temperature of 80 °C, following deposition for 24 h. The grain sizes of the Sm2S3 first increase and then decrease with increasing pH value. The as–deposited thin films exhibit a dense and crystallinized surface morphology. The film shows good transmittance in visible spectrum and excellent absorbency of ultraviolet light, and the bandgap of the thin films at pH of 3.0 is calculated to be 4.06 eV.


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.


2011 ◽  
Vol 25 (16) ◽  
pp. 2149-2156
Author(s):  
JICHENG ZHOU ◽  
XUQIANG ZHENG ◽  
ZHIJIE SHI ◽  
BAOXING ZHAO ◽  
FU LIU ◽  
...  

SiCO thin-films doped with aluminum (Al) prepared by alternate deposition of SiC and Al thin layers using Ar and O 2 as sputtering gas were deposited on n- Si substrates. The as-deposited thin-films were annealed under 600°C in nitrogen ambient. The thin-films have been characterized by atomic force microscopy, energy dispersive spectrometer, X-ray diffraction, fourier transform infrared spectroscopy, and photoluminescence spectra. The results showed that the introduction of Al promotes the formation of Si — C bonds, but hinders amorphous SiC to further transform to crystalline SiC . The doped Al would react with SiO x in the thin-films to form more Si particles which strongly affect the optical properties. After Al doped, there presented a seven times of enhancement emission band centered around 412 nm, which is ascribed to nanostructure Si -related defect centers embedded in the SiCO thin-films. The obtained results are expected to have important applications in modern optoelectronic devices.


2006 ◽  
Vol 306-308 ◽  
pp. 1295-1300
Author(s):  
J.S. Choi ◽  
J.S. Kim ◽  
I.S. Byun ◽  
B.H. Park

We have investigated structural and electrical properties of PbZr0.3Ti0.7O3 (PZT) thin films deposited by pulsed laser deposition methods. In order to improve the ferroelectric properties of PZT thin films, we have controlled grain size or surface morphology by changing bottom electrode or deposition time. PZT thin films have been deposited on La0.5Sr0.5CoO3 (LSCO) or LaMnO3 (LMO) bottom electrodes with LaAlO3 substrates during different deposition times. X-ray diffraction data have shown that all the PZT films and bottom electrodes are highly oriented with their c-axes normal to the substrates. The thickness of each film is determined by field-emission scanning electron microscope. We have also observed alternation of grain sizes (80~180 nm) by using atomic force microscopy mode and surface potential distribution and retention behavior of ferroelectric domains by using Kelvin force microscopy mode. A PZT/LMO structure has shown superior ferroelectric and retention properties to a PZT/LSCO structure.


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