VERY HIGH TUNABILITY OF BaSnxTi1-xO3 FERROELECTRIC THIN FILMS DEPOSITED BY SOL-GEL

2011 ◽  
Vol 04 (01) ◽  
pp. 49-52 ◽  
Author(s):  
MANUEL MASCOT ◽  
DIDIER FASQUELLE ◽  
JEAN-CLAUDE CARRU

Ba(Sn0.02Ti0.98)O3 thin films (BTS) were prepared by sol-gel route and deposited by spin-coating on commercial Pt/Ti/SiO2/Si substrates. By modifying the annealing conditions from 750°C for 1 h to 950°C for 15 min, the grain size increased from 60 nm to 110 nm due to the increased driving force. The dielectric permittivity ε′ and tunability nr are correlated with the grain size: these parameters increase with the grain size. At room temperature for the BST film annealed at 950°C, a record value of 76% of tunability is obtained at 10 kHz. This very high value of tunability makes BaSnTiO 3 a very good candidate for tunable devices.

2015 ◽  
Vol 08 (01) ◽  
pp. 1550015 ◽  
Author(s):  
Manuel Mascot ◽  
Jean-Claude Carru ◽  
Didier Fasquelle

Ba ( Sn 0.02 Ti 0.98) O 3 thin films (BTS) were prepared by sol–gel route and deposited by spin-coating on commercial Pt / Ti / SiO 2/ Si substrates. By modifying the annealing conditions from 750°C at 1 h to 950°C at 15 min, the relative tunability nr at 100°C in the paraelectric state increased from 45 to 70% while the DC dielectric permittivity ε′(0) increased as well. The evolutions of ε′(E) and nr(E) are explained from Devonshire thermodynamic formalism. The very high value of tunability of 70% is explained by the grain size increase of our BTS thin films and the decrease of the dead layer effect when the annealing conditions are optimized.


2006 ◽  
Vol 514-516 ◽  
pp. 245-249 ◽  
Author(s):  
Olena Okhay ◽  
Vitor M.X. Bergano ◽  
Ai Ying Wu ◽  
Paula M. Vilarinho

Crystalline (Sr1-1.5xBix)TiO3 (SBiT) thin films (0.002 ≤ x ≤ 0.5) were prepared by sol-gel on Pt/TiO2/SiO2/Si substrates. Cubic monophasic SBiT films were obtained for samples with x ≤ 0.167. For films with x ≥ 0.267 a second phase identified as Bi4Ti3O12 was observed. The lattice parameter of SBiT films increases with increasing Bi content, similar to the variation observed in SBiT ceramics. No obviously variation of the grain size with the Bi content was observed. The dielectric constant ε´ at room temperature increases with increasing of Bi concentrations up to x ≤ 0.1. The loss tangent of Bi doped SrTiO3 films is approximately 0.05 and lower than undoped ST films at 10kHz. The higher values of ε´ of Bi doped ST films with x=0.1 and x=0.167 in comparison with undoped films may suppose the appearance of a dielectric anomaly at low temperatures, which will be dependent on the Bi content.


Author(s):  
Ibrahim Mohd Yazid ◽  
Muhammad Hazim Raselan ◽  
Shafinaz Sobihana Shariffudin ◽  
Puteri Sarah Mohamad Saad ◽  
Sukreen Hana ◽  
...  

2013 ◽  
Vol 594-595 ◽  
pp. 113-117 ◽  
Author(s):  
Dewi Suriyani Che Halin ◽  
Ibrahim Abu Talib ◽  
Abdul Razak Daud ◽  
Muhammad Azmi Abdul Hamid

Copper oxide films were prepared via sol-gel like spin coating starting from methanolic solutions of cupric chloride onto the TiO2 substrates. Films were obtained by spin coating under room conditions (temperature, 25-30 °C) and were subsequently annealed at different temperatures (200-400 °C) in oxidizing (air) and inert (N2) atmospheres. X-ray diffraction (XRD) patterns showed crystalline phases, which were observed as a function of the annealing conditions. The film composition resulted single or multi-phasic depending on both temperature and atmosphere. The grain size of film was measured using scanning electron microscopy (SEM) and the surface roughness of thin films was characterized by atomic force microscopy (AFM). The grain size of which was annealed in air at 300 °C was 30.39 nm with the surface roughness of 96.16 nm. The effects of annealing atmosphere on the structure and morphology of copper oxide thin films are reported.


2009 ◽  
Vol 1199 ◽  
Author(s):  
Danilo G Barrionuevo ◽  
Surinder P Singh ◽  
Maharaj S. Tomar

AbstractWe synthesized BiFe1-xMnxO3 (BFMO) for various compositions by sol gel process and thin films were deposited by spin coating on platinum Pt/Ti/SiO2/Si substrates. X-ray diffraction shows all the diffraction planes corresponding to rhombohedrally distorted perovskite BiFeO3 structure. The absence of any impurity phase in the films suggests the incorporation Mn ion preferentially to Fe site in the structure for low concentration. Magnetic measurements reveal the formation of ferromagnetic phase at room temperature with increased Mn substitution. On the other hand, ferroelectric polarization decreases with increasing Mn ion concentration. Raman studies suggest the dopant induced structural distortion.


2011 ◽  
Vol 277 ◽  
pp. 1-10 ◽  
Author(s):  
D. Fasquelle ◽  
M. Mascot ◽  
J.C. Carru

This paper reports a study of Ba0.9Sr0.1TiO3films deposited on Pt/Ti/SiO2/Si substrates. The annealing temperatures were 750°C, 850°C and 950°C. An increase of the average size of grains was observed, from 60 nm at 750°C to 110 nm at 950°C, as well as an increase of the dielectric constant, remnant polarization and tunability. When the annealing time was decreased from 1 hour to 15 min, the dielectric constant and remnant polarization values have been increased. The optimized annealing conditions (950°C for 15 min) give the following results: εr= 780 and tgδ = 0.01 at 100 kHz, Pr = 13 µC/cm², Ec = 63 kV/cm and a tunability of 55%.


2017 ◽  
Vol 268 ◽  
pp. 244-248
Author(s):  
Abu Hassan Haslan ◽  
Imad Hussein Kadhim

High-quality nanocrystalline (NC) SnO2 thin films were grown on SiO2/Si and Al2O3 substrates using sol–gel spin coating method. The structural properties, surface morphologies and gas sensing properties of the NC SnO2 were investigated. XRD measurements showed a tetragonal rutile structure and the diffraction peaks for NC SnO2 thin films grown on Al2O3 substrates outperformed those of NC SnO2 films grown on SiO2/Si substrates. The surface morphology of the annealed SnO2 thin films at 500 °C appeared as polycrystalline with uniform nanoparticle distribution. Hydrogen (H2) gas sensing performance of the NC SnO2 was examined for H2 concentrations ranging from 150 ppm to 1000 ppm at different temperatures (room temperature, 75 and 125 °C) for over 50 min. The room temperature sensitivities for H2 gas sensors based on NC SnO2 thin films grown on Al2O3 and SiO2/Si substrates was 2570% and 600%, respectively upon exposure to 1000 ppm of H2 gas. While the sensitivity values at 125 °C increased to 9200% and 1950%, respectively.


2011 ◽  
Vol 104 (4) ◽  
pp. 1129-1136 ◽  
Author(s):  
M. Thambidurai ◽  
N. Muthukumarasamy ◽  
N. Murugan ◽  
Dhayalan Velauthapillai ◽  
S. Agilan ◽  
...  

2009 ◽  
Vol 08 (03) ◽  
pp. 299-303 ◽  
Author(s):  
SAJJAD DEHGHANI ◽  
ABDOLGHAFAR BARZEGAR ◽  
MOHAMMAD HOSSEIN SHEIKHI

Ferroelectric PbZr 1-x Ti x O 3 (PZT) thin films have been extensively investigated because of their excellent piezoelectric, pyroelectric, ferroelectric, and dielectric properties. Sol–gel synthesis and spin-coating are popular routes to the formation of high quality, dense, and crack-free thin films. In this work, high quality, crack-free PZT thin films have been prepared by sol–gel method via spin-coating on Pt/Ti/SiO2/Si substrate by different temperature processings. The crystallographic and morphological properties of the films have been analyzed by X-ray diffraction and scanning electron microscopy. The electrical properties of thin films including the permittivity, loss tangent, and polarization–voltage hysteresis loop were measured and compared for different films. Finally, by optimizing temperature processing, highly textured and high quality films of PZT with perovskite phase were obtained on Pt/Ti/SiO2/Si substrates.


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