Influence of thickness on crystallization and properties of LiNbO3 thin films

Thin films of lithium niobate were deposited on Pt/Ti/SiO2 (111) substrates by spin coating from the polymeric precursor method (Pechini process). Annealing in static air was performed at 500 degreesC for 3 h. The obtained films were characterized by X-ray diffraction and atomic force microscopy. The dielectric constant, dissipation factor and resistance were measured in frequency region from 10 Hz to 10 MHz and the hysteresis loop was obtained. The influence of number of layers on crystallization, morphology and properties of LiNbO3 thin films is discussed. (C) 2003 Elsevier B.V. All rights reserved.

Electrical properties of lanthanum doped Bi4Ti3O12 thin films annealed in different atmospheres

Pure-and lanthanun doped Bi4Ti3O12 thin films were deposited on Pt/Ti/SiO2/Si substrate using a polymeric precursor solution. Annealing in static air and oxygen atmosphere was performed at 700 degrees C for 2 h. The obtained films were characterized by X-ray diffraction and atomic force microscopy. The dielectric constant and dissipation factor were measured in the frequency region from 1 kHz to 1 MHz. Electrical characterization of the films pointed to ferroelectricity via hysteresis loop. Films annealed in static air possess a dielectric constant higher than films annealed in oxygen atmosphere due to differences in the grain size, crystallinity and structural defects. A regularly shaped hystereses loop is observed after annealing in static air. The obtained results suggest that the annealing in oxygen atmosphere can increase the trapped charge and the relaxation phenomenon. (c) 2006 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Influence of oxygen atmosphere on crystallization and properties of LiNbO3 thin films

Thin films of lithium niobate were deposited on the Pt/Ti/SiO2 (111) substrates by spin coating from the polymeric precursor method (Pechini process). Annealing in static air and oxygen atmosphere was performed at 500 degreesC for 3 h. The films obtained were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The dielectric constant and dissipation factor were measured in frequency region from 10 Hz to 10 MHz. Electrical characterization of the films pointed to ferroelectricity via hysteresis loop. The influence of oxygen atmosphere on crystallization, morphology and properties of LiNbO3 thin films is discussed. (C) 2003 Elsevier Ltd. All rights reserved.

Characterization of lanthanum-doped bismuth titanate thin films prepared by polymeric precursor method

Lanthanum-modified bismuth titanate, Bi4-xLaxTi3O12 (BLT), with x ranging from 0 to 0.75 was grown on Pt/Ti/SiO2/Si substrates using a polymeric precursor solution and spin-coating method. The dielectric constant of highly doped bismuth titanate was equal to 148 while dielectric losses remained low (tan delta = 0.0018), and the films showed well-saturated polarization-electric field curves (2P(r) = 40.6 muC/cm(2) and V-c = 0.99 V). The leakage current densities improve for the lanthanum-doped system. For five-layered BLT films with x = 0.75, a charge storage density of 35 fC/mum(2) and a thickness of 320 nm were found. (C) 2004 Elsevier B.V. All rights reserved.

Effect of annealing atmosphere on phase formation and electrical characteristics of bismuth ferrite thin films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dependence of annealing time on structural and morphological properties of Ca(Zr0.05Ti0.95)O-3 thin films

Ca(Zr0.05Ti0.95)O-3 (CZT) thin films were prepared by the polymeric precursor method by spin-coating process. The films were deposited on Pt(1 1 1)/Ti/SiO2/Si(1 0 0) substrates and annealed at 650 degrees C for 2,4, and 6 It in oxygen atmosphere. Structure and morphology of the CZT thin films were characterized by the X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM) and field-emission scanning electron microscopy (FEG-SEM). XRD revealed that the film is free of secondary phases and crystallizes in the orthorhombic structure. The annealing time influences the grain size, lattices parameter and in the film thickness. (c) 2006 Elsevier B.V. All rights reserved.

Improvement of fatigue resistance on La modified BiFeO(3) thin films

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Piezoresponse behavior of niobium doped bismuth ferrite thin films grown by chemical method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Very Intense Distinct Blue and Red Photoluminescence Emission in MgTiO3 Thin Films Prepared by the Polymeric Precursor Method: An Experimental and Theoretical Approach

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of oxidizing atmosphere on ferroelectric and piezoelectric response of CaBi2Nb2O9 thin films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Retention Characteristics of CBTi144 Thin Films Explained by Means of X-Ray Photoemission Spectroscopy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Multi-functional properties of CaCu3Ti4O12 thin films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ferroelectric and microstructural characteristics of SrBi2Ta2O9 thin films crystallized by the rapid thermal annealing process

Ferroelectric SrBi2Ta2O9 thin films on Pt/Ti/SiO2/Si were successfully synthesized by the modified polymeric precursor method. The films were deposited by spin coating and crystallized by rapid thermal annealing in a halogen lamp furnace, followed by postannealing at temperatures ranging from 700 degreesC to 800 degreesC in an oxygen atmosphere. Microstructural and phase evaluations were followed by x-ray diffraction and atomic force microscopy. The films displayed spherical grain structures with a superficial roughness of approximately 3-6 nm. The dielectric constant values were 121 and 248 for films treated at 700 degreesC and 800 degreesC, respectively. The P-E curve showed a voltage shift toward the positive side, which was attributed to crystallization under the halogen illumination. The remanent polarization (2P(r)) and coercive field (E-c) were 7.1 muC/cm(2) and 113 kV/cm, and 18.8 muC/cm(2) and 93 kV/cm for the films treated at 700 degreesC and 800 degreesC, respectively. (C) 2001 American Institute of Physics.

Control of retention and fatigue-free characteristics in CaBi4Ti4O15 thin films prepared by chemical method

Ferroelectric CaBi4Ti4O15 (CBTi144) thin films were deposited on Pt/Ti/SiO2/Si substrates by the polymeric precursor method. The films present a single phase of layered-structured perovskite with polar axis orientation after annealing at 700 degrees C for 2 h in static air and oxygen atmosphere. The a/b-axis orientation of the ferroelectric film is considered to be associated with the preferred orientation of the Pt bottom electrode. It is noted that the films annealed in static air showed good polarization fatigue characteristics at least up to 10(10) bipolar pulse cycles and excellent retention properties up to 10(4) s. on the other hand, oxygen atmosphere seems to be crucial in the decrease of both, fatigue and retention characteristics of the capacitors. Independently of the applied electric field, the retained switchable polarization approached a nearly steady-state value after a retention time of 10 s. (C) 2006 Elsevier B.V. All rights reserved.

Soft chemical deposition of BiFeO3 multiferroic thin films

BiFeO3 thin films free of secondary phases were obtained by the soft chemical solution on Pt(111)/Ti/SiO2/Si substrates after annealing at 500 degrees C for 2 h. The film grown in the (100) direction presented a remanent polarization P-r of 31 mu C/cm(2) at room temperature. Electrical measurements using both quasistatic hysteresis and pulsed polarization confirm the existence of ferroelectricity with a switched polarization of 60-70 mu C/cm(2), Delta P=(P-*-P). Low leakage conduction and an out-of-plane piezoelectric (d(3)) coefficient of 40 pm/V were obtained by the improvement of preparation technology.