Photoluminescent Spectrum Changes Associated With Remanent Polarization Degradation in Sub-100-nm-thick europium-doped Strontium Bismuth Tantalate Red-phosphor Thin Films

AbstractEffects of off-stoichiometry and Nb substitution on the dielectric anomaly and ferroelectric properties have been investigated for SrBi2Ta2O9(SBT) thin films. Local atomic environment for the stoichiometric and off-stoichiometric SBT films has been also measured. The features of the dielectric anomaly, the Curie temperature (Tc), and the temperature dependence of the spontaneous polarization (Ps) are independent of the film thickness, and are governed by the nature of the crystal. For the stoichiometric Sr content SBT films, the grain size increases and the temperature dependence of the remanent polarization (Pr) decreases with increasing thickness. For the films with Sr/Bi/Ta = 0.8/2/2 and 0.8/2.2/2, Sr deficient local structure was observed, and such lattice structure probably leads to higher Tc than the stoichiometric crystal. Nb substitution for Ta also raises Tc, and makes the dielectric anomaly sharper. The phase transition associated with the dielectric anomaly for these films is thought to be first-order.

Download Full-text

Influence of Ta content on the physical properties of SrBi2Ta2O9 ferroelectric thin films

Journal of Materials Research ◽

10.1557/jmr.2006.0383 ◽

2006 ◽

Vol 21 (12) ◽

pp. 3124-3133 ◽

Cited By ~ 1

Author(s):

Fan-Yi Hsu ◽

Ching-Chich Leu ◽

Chao-Hsin Chien ◽

Chen-Ti Hu

Keyword(s):

Thin Films ◽

Physical Properties ◽

Spin Coating ◽

Coercive Field ◽

Remanent Polarization ◽

Ferroelectric Properties ◽

Ferroelectric Thin Films ◽

Preferential Orientation ◽

Strontium Bismuth Tantalate ◽

Metalorganic Decomposition

We have investigated the effect that the Ta content has on the ferroelectric properties of strontium bismuth tantalate (SBT) thin films synthesized using metalorganic decomposition (MOD) and spin coating techniques. The physical properties of these SBT samples were strongly dependent upon the Ta ratio. Polarization measurements revealed that Ta-deficient SBT exhibited a relatively low coercive field (2Ec ∼ 87 kV/cm) and a high remanent polarization (2Pr ∼ 15 μC/cm2). The value of 2Pr decreased as the Ta ratio in SBT increased. The improved ferroelectric properties of the Ta-deficient SBT samples may have resulted from the uniformly well-grown bismuth-layered-structured (BLS) phases of the films and their highly preferential orientation along the a and b axes. We suggest that the incorporation of Ta vacancies plays an important role in enhancing the crystallinities and microstructures of Ta-deficient SBT films.

Download Full-text

Improvement in Ferroelectric Properties of Sol-Gel Derived SrBi2Ta2O9 thin films with seeding layers

MRS Proceedings ◽

10.1557/proc-718-d10.11 ◽

2002 ◽

Vol 718 ◽

Author(s):

Ching-Chich Leu ◽

Chao-Hsin Chien ◽

Ming-Jui Yang ◽

Ming-Che Yang ◽

Tiao-Yuan Huang ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Magnetron Sputtering ◽

Remanent Polarization ◽

Ferroelectric Properties ◽

Sol Gel ◽

Strontium Bismuth Tantalate ◽

Seeding Layer ◽

Si Substrates ◽

Nucleation Sites

AbstractThe effects of a seeding layer, which was deposited on Pt/TiO2/SiO2/Si substrates using magnetron sputtering, on the characteristics of sol-gel-deposited strontium-bismuth-tantalate (SBT) thin films are investigated. The seeding layer serves as nucleation sites so homogeneous crystalline SBT films of bismuth-layered structure (BLS) with fine grains are successfully obtained by 750°C rapid thermal annealing in O2 ambient. The remanent polarization (2Pr) improves from 12.1 to 18.8 μC/cm2 with the addition of the seeding layer. In addition, the seeding layer also results in a lower nucleation temperature, allowing the use of 700°C annealing for 10 min to grow SBT films that are fully crystallized with BLS phase and shows good ferroelectric properties. Finally, crystallinity and microstructures of SBT films are found to be strongly dependent on the thickness of the seeding layer. Optimum Ta-seeded SBT thin film crystallized at 700°C for 10min depicts a higher 2Pr value (12.9 μC/cm2 (@5V) than that of the un-seeded films crystallized at 750°C for 1min.

Download Full-text

PREPARATION AND FERROELECTRIC PROPERTY OF (100)-ORIENTED Ca0.4Sr0.6Bi4Ti4O15 THIN FILM ON Pt/Ti/SiO2/Si SUBSTRATE

Surface Review and Letters ◽

10.1142/s0218625x10014351 ◽

2010 ◽

Vol 17 (05n06) ◽

pp. 445-449 ◽

Cited By ~ 1

Author(s):

SUHUA FAN ◽

QUANDE CHE ◽

FENGQING ZHANG

Keyword(s):

Thin Film ◽

Thin Films ◽

Ferroelectric Property ◽

Remanent Polarization ◽

Sol Gel ◽

Xrd Analysis ◽

Sem Analysis ◽

Si Substrate ◽

Degree Of Orientation ◽

Equiaxed Grains

The (100)-oriented Ca0.4Sr0.6Bi4Ti4O15(C0.4S0.6BTi ) thin film was successfully prepared by a sol-gel method on Pt/Ti/SiO2/Si substrate. The orientation and formation of thin films under different annealing schedules were studied using XRD and SEM. XRD analysis indicated that (100)-oriented C0.4S0.6BTi thin film with degree of orientation of I(200)/I(119) = 1.60 was prepared by preannealing the film at 400°C for 3 min followed by rapid thermal annealing at 800°C for 5 min. SEM analysis further indicated that the (100)-oriented C0.4S0.6BTi thin film with a thickness of about 800 nm was mainly composed of equiaxed grains. The remanent polarization and coercive field of the film were 16.1 μC/cm2 and 85 kV/cm, respectively.

Download Full-text

Synthesis and Ferroelectric Properties of Sol–Gel Derived Intergrowth-Superlattice-Structured SrBi4Ti4O15-Bi4Ti3O12 Thin Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.1781 ◽

2011 ◽

Vol 197-198 ◽

pp. 1781-1784

Author(s):

Hua Wang ◽

Jian Li ◽

Ji Wen Xu ◽

Ling Yang ◽

Shang Ju Zhou

Keyword(s):

Thin Films ◽

Remanent Polarization ◽

Annealing Temperature ◽

Ferroelectric Properties ◽

Sol Gel ◽

Hysteresis Loops ◽

Si Substrates ◽

Gel Processing ◽

Coercive Electric Field ◽

Clockwise Hysteresis

Intergrowth-superlattice-structured SrBi4Ti4O15–Bi4Ti3O12(SBT–BIT) films prepared on p-Si substrates by sol-gel processing. Synthesized SBT–BIT films exhibit good ferroelectric properties. As the annealing temperature increases from 600°C to 700°C, the remanent polarization Prof SBT–BIT films increases, while the coercive electric field Ecdecreases. SBT–BIT films annealed at 700°C have a Prvalue of 18.9µC/cm2which is higher than that of SBT (16.8µC/cm2) and BIT (14.6µC/cm2), and have the lowest Ecof 142 kV/cm which is almost the same as that of SBT and BIT. The C-V curves of Ag/SBT-BIT/p-Si heterostructures show the clockwise hysteresis loops which reveal the memory effect due to the polarization. The memory window in C-V curve of Ag/SBT-BIT/p-Si is larger than that of Ag/SBT/p-Si heterostructure or Ag/BIT/p-Si heterostructure.

Download Full-text

Ferroelectric Properties and Microstructures of Bi4-xDyxTi3O12 Thin Films

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.633.378 ◽

2014 ◽

Vol 633 ◽

pp. 378-381

Author(s):

Bei Li ◽

X.B. Liu ◽

M. Chen ◽

X.A. Mei

Keyword(s):

Thin Films ◽

Electrical Properties ◽

Layered Structure ◽

Remanent Polarization ◽

Single Phase ◽

Ferroelectric Properties ◽

Pulsed Laser ◽

Laser Deposition ◽

Deposition Technique ◽

Si Substrates

Dy-doped Bi4Ti3O12 thin films were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition technique, and the structures and electrical properties of the films were investigated. XRD results indicated that all of Bi4-xDyxTi3O12 films consisted of single phase of a bismuth-layered structure with well-developed rod-like grains. The remanent polarization ( Pr ) and coercive field (Ec) of the Bi4-xDyxTi3O12 Film with x=0.75 were 25μC/cm2 and 85KV/cm , respectively.

Download Full-text

Ga-doping effects on electrical and luminescent properties of ZnO:(La,Eu)OF red phosphor thin films

Journal of Applied Physics ◽

10.1063/1.1594817 ◽

2003 ◽

Vol 94 (4) ◽

pp. 2411-2416 ◽

Cited By ~ 66

Author(s):

Shinobu Fujihara ◽

Akira Suzuki ◽

Toshio Kimura

Keyword(s):

Thin Films ◽

Luminescent Properties ◽

Red Phosphor ◽

Doping Effects ◽

Ga Doping

Download Full-text

Properties of RF Magnetron Sputtered Sr0.4Ba0.6Nb1.85Ta0.15O6 Thin Films

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.284-287.193 ◽

2013 ◽

Vol 284-287 ◽

pp. 193-197

Author(s):

Cheng Fu Yang ◽

Wen Cheng Tzou

Keyword(s):

Thin Films ◽

Remanent Polarization ◽

Annealing Temperature ◽

Emission Mechanism ◽

Grain Sizes ◽

Conventional Furnace ◽

Saturation Polarization ◽

Frenkel Emission ◽

Current Densities ◽

Xrd Patterns

Sr0.4Ba0.6Nb1.85Ta0.15O6 (SBNT) ceramic was used as a target and SBNT thin films were deposited at room temperature. After deposition, the SBN thin films were annealed in conventional furnace (CFA) and in an oxygen atmosphere for 1h by changing the temperature from 700oC to 900oC. The thicknesses of the SBN thin films were calculated by SEM and they were about 450nm independent on the annealing temperature. From the XRD patterns, the as-deposited SBNT thin films displayed amorphous phase, whereas as CFA-treatment was used, the SBNT thin films displayed smooth surfaces. The grain sizes also increased with increasing CFA-treated temperature. In addition, the remanent polarization and saturation polarization increased and coercive field decreased with increasing CFA-treated temperature. Finally, the lnJ-E1/2 curves of the SBNT thin films was developed to find that the linear variations of leakage current densities correspond either to the Schottky emission mechanism or to the Poole-Frenkel emission mechanism.

Download Full-text

High Remanent Polarization in Laser Ablated SrBi2Nb2O9Thin Films

MRS Proceedings ◽

10.1557/proc-780-y1.7 ◽

2003 ◽

Vol 780 ◽

Author(s):

Rasmi R. Das ◽

P. Bhattacharya ◽

W. Pérez ◽

Ram S. Katiyarxya

Keyword(s):

Thin Films ◽

Film Thickness ◽

Coercive Field ◽

Remanent Polarization ◽

Annealing Temperature ◽

Dielectric Breakdown ◽

Breakdown Strength ◽

Suitable Material ◽

Average Grain Size ◽

Degree Of Orientation

AbstractPulsed-laser-deposition technique was used to grow SrBi2Nb2O9(SBN) thin films on platinized silicon substrates. The effect of annealing temperature and film thicknesses on the structural and electrical properties has been studied. The average grain size and rms surface roughness was found to increase with increasing annealing temperature. The degree of orientation along the (200) direction was increased with the film thicknesses. The remanent polarization was found to be increased with the film thicknesses and was attributed to the selftexturing characteristics of SBN films. Thin films with higher thickness (∼570 nm) exhibited high value of remanent polarization (∼38 ν/cm2) with coercive field of 185 kV/cm. There was a reduction of coercive field with the film thickness. The dielectric constant was observed to be independent of the film thickness. The increase in loss tangent with increasing film thicknesses was attributed to the reduction of dielectric breakdown strength of the films. The SBN thin films showed minimal fatigue characteristics and suitable material for memory devices.

Download Full-text