Transmission Electron Microscopy of Pzt Thin-Films Prepared by A Sol-Gel Technique

1993 ◽  
Vol 310 ◽  
Author(s):  
Supapan Seraphin ◽  
Dan Zhou ◽  
G. Teowee ◽  
J.M. Boulton ◽  
D.R. Uhlmann

AbstractThe microstructure of lead zirconate titanate (PZT) thin films prepared by a sol-gel technique was investigated using transmission electron microscopy (TEM) and transmission electron diffraction. We investigated the microstructure of three sets of thin films with different chemical compositions: PZT 53/47 films with no excess PbO; with excess PbO; and PZT 65/35 with no excess PbO. All samples were fired for 30 minutes at temperatures ranging from 400C to 700C. Incorporation of excess PbO in the 53/47 film fired at 450C resulted in polycrystalline perovskite grains with an average grain size of less than 0.1 μm. Grain boundaries are decorated by 5-10 nm diameter precipitates possibly caused by the segregation of remnant pyrochlore or excess PbO. The films have high values of dielectric constant (up to 2500) when fired at 700C. PZT 65/35 fired at 700C consists of two distinct phases: a fine-grained matrix of pyrochlore, and 10-μm diameter rosettes of perovskite. The correlations between the compositions, the microstructure of the films, and their processing conditions on the one hand, and ferroelectric properties on the other are discussed.

1997 ◽  
Vol 12 (6) ◽  
pp. 1441-1444 ◽  
Author(s):  
L. Armelao ◽  
A. Armigliato ◽  
R. Bozio ◽  
P. Colombo

The microstructure of Fe2O3 sol-gel thin films, obtained from Fe(OCH2CH3)3, was investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy. Samples were nanocrystalline from 400 °C to 1000 °C, and the crystallized phase was haematite. In the coatings, the α–Fe2O3 clusters were dispersed as single particles in a network of amorphous ferric oxide.


2003 ◽  
Vol 18 (6) ◽  
pp. 1289-1292 ◽  
Author(s):  
Zhiwen Chen ◽  
J. K. L. Lai ◽  
C. H. Shek ◽  
Haydn Chen

Nanocrystalline tin dioxide (SnO2) thin films were prepared on glass substrate by pulse laser deposition for the first time. The thin films were characterized for their composition, morphology, and crystalline structure by x-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. It was found that the thin films consisted only of the tetragonal phase SnO2 with no structural change, and they were well crystallized during deposition. In most cases, SnO2 particles were overlapped, predominantly grown on preferred (101) plane, and connected with two or three neighbors through necks. The average grain size of the as-prepared thin films was about 12 nm. These facts are of great importance for sensor characteristics, since smaller grains and preferred orientation properties provide higher gas sensitivity to the whole thin films. Our findings indicate that the n-type wide-band-gas semiconductor nanocrystalline thin films can be manipulated by using pulse laser deposition techniques, offering new opportunities to control material fabrication.


2001 ◽  
Vol 16 (6) ◽  
pp. 1626-1631 ◽  
Author(s):  
A. Karthikeyan ◽  
Rui M. Almeida

An investigation of phase separation phenomena in gel and glassy thin films of silica–titania, with TiO2 contents of 20 and 40 mol%, has been carried out by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The thin films were prepared by spin coating of a precursor sol on silicon wafers. Both the TEM measurements (carried out on scrapped thin film flakes) and the AFM measurements (carried out on films coated on the silicon substrates) for samples with different heat treatments suggest that spinodal-like structural inhomogeneities occur in these samples, unlike the corresponding observations in pure silica films, which are known to be homogeneous. Changes in the microstructure of the films have been noticed with the thermal treatment, in agreement with earlier x-ray photoemission studies. The finer characteristic dimensions of the phase separated regions reveal that silica–titania samples prepared by sol-gel processing exhibit a more intimate mixing of the phases.


2002 ◽  
Vol 17 (8) ◽  
pp. 2066-2074 ◽  
Author(s):  
Zhaoxia Zhou ◽  
Ian M. Reaney ◽  
David Hind ◽  
Steven J. Milne ◽  
Andy P. Brown ◽  
...  

Advanced analytical transmission electron microscopy has been used to investigate microstructural evolution during pyrolysis in triol-based sol-gel thin films. At pyrolysis temperatures up to 300 °C, the films remained amorphous; however, nanometer-sized precipitates were observed in films heat-treated up to 400 °C for 10 min. Analytical transmission electron microscopy indicated that the precipitates were Pb-rich, as well as deficient in O, Ti, and Zr. Films pyrolyzed up to 500 °C for 10 min were composed of a nanocrystalline pyrochlore phase; however, pores could be observed, situated in the same position as the nanometer-sized precipitates at 400 °C. Face-centered cubic Pb-rich crystallites were also present on the surface of pyrolyzed films but absent in the fully crystallized films annealed at 650 °C. A tentative mechanism is proposed to explain these observations.


2004 ◽  
Vol 19 (5) ◽  
pp. 1504-1508 ◽  
Author(s):  
Bin-Siang Tsai ◽  
Yen-Hwei Chang ◽  
Yu-Chung Chen

Nano-grained phosphors of Eu3+-doped MgGa2O4 crystallites were prepared by sol-gel technique. The characterization and optical properties of luminescent MgGa2O4:Eu3+ powders have been investigated. The dried sol-gel powders were calcined in air at different temperature from 600 to 1000 °C for 5 h. The x-ray diffraction profiles showed that the MgGa2O4:Eu3+ powders began to crystallize around 600 °C and formed stable MgGa2O4 phase in the temperature range of 600–900 °C. The transmission electron microscopy morphology observations revealed that the fired powders exhibit small grain size less than 20 nm. In the PL studies, under ultraviolet (394 nm) excitation, the calcined powders emitted bright red luminescence (615 nm, 5D0→7F2), and the powders fired at 900 °C were found to have the maximum photoluminescence intensity. The quenching concentration of Eu3+ in MgGa2O4 crystallites was also indicated to be about 5∼6 mol%.


RSC Advances ◽  
2016 ◽  
Vol 6 (51) ◽  
pp. 44987-44992 ◽  
Author(s):  
Sophie Guillemin ◽  
Vincent Consonni ◽  
Laetitia Rapenne ◽  
Eirini Sarigiannidou ◽  
Fabrice Donatini ◽  
...  

The luminescence lines related to extended defects and interfaces in polycrystalline ZnO thin films grown by sol–gel process are investigated by combining photoluminescence and cathodoluminescence imaging with high-resolution transmission electron microscopy.


1997 ◽  
Vol 12 (4) ◽  
pp. 1043-1047 ◽  
Author(s):  
Chang Jung Kim ◽  
Dae Sung Yoon ◽  
Joon Sung Lee ◽  
Chaun Gi Choi ◽  
Kwangsoo No

The lead zirconate titanate (PZT) thin films were fabricated using sol-gel spin coating onto Pt/Ti/glass substrates. Effects of the holding time for pyrolysis and the coating cycle on the preferred orientation of the PZT thin films were studied. The films were fabricated with different coating cycles (3, 5, 7, 9, 11), dried at 330 °C for different holding times (5, 30, 60 min), and then annealed at the same temperature of 650 °C using rapid thermal annealing (RTA). The preferred orientations of the films were investigated using x-ray diffraction and glancing angle x-ray diffraction. The microstructure and the selected area diffraction pattern of the PZT thin films were also investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively.


1999 ◽  
Vol 596 ◽  
Author(s):  
Zhan-jie Wang ◽  
Ryutaro Maeda ◽  
Kaoru Kikuchi

AbstractLead zirconate titanate (PZT) thin films were fabricated by a three-step heat-treatment process which involves the addition of -10, 0 and 10 mol% excess Pb to the starting solution and spin coating onto Pt/Ti/SiO2/Si substrates. Crystalline phases as well as preferred orientations in PZT films were investigated by X-ray diffraction analysis (XRD). The microstructure and composition of the films were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron probe microanalysis (EPMA), respectively. The well-crystallized perovskite phase and the (100) preferred orientation were obtained by adding 10% excess Pb to the starting solution. It was found that PZT films to which 10% excess Pb was added had better electric properties. The remanent polarization and the coercive field of this film were 34.8 μC/cm2 and 41.7 kV/cm, while the dielectric constant and loss values measured at 1 kHz were approximately 1600 and 0.04, respectively. Dielectric and ferroelectric properties were correlated to the microstructure of the films.


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