MICROSTRUCTURE AND PROPERTIES OF FERROELECTRIC Bi4Ti3O12 THIN FILMS

1999 ◽  
Vol 13 (26) ◽  
pp. 933-945 ◽  
Author(s):  
B. JIANG ◽  
J. L. PENG ◽  
L. A. BURSILL ◽  
H. WANG

The film morphology and defect structure of ferroelectric bismuth titanate thin films are studied by high resolution transmission electron microscopy. As-grown and RTA-processed thin films have similar defect structures, consisting of stacking faults and complex intergrowth defect structures. The as-grown specimens prepared at low temperature had smaller particle size with higher density of these defects compared to RTA-processed samples. Detailed atomic structure models for the stacking faults and intergrowth defect structures are proposed and the computer-simulated images are compared with experiment.

1991 ◽  
Vol 230 ◽  
Author(s):  
T. L. Lee ◽  
L. J. Chen ◽  
F. R. Chen

AbstractHigh resolution and conventional transmission electron microscopy have been applied to study the interfacial reaction of yttrium thin films on Si. Epitaxial Ysi2−x film was grown on (111)Si by rapid thermal annealing at 500–1000 °C. The orientation relationship between yttrium silicide and (111)Si was determined to be [0001]Ysi2−x//[111]Si and (1010)Ysi2−x//(112)Si. The vacancies in the Ysi2−x film were found to be ordered in the Si sublattice plane and form an out-of-step structure. The range of M values of the out-of-step structure was found to narrow with annealing temperature and time. Defects along specific crystallographic directions were observed and analyzed to be intrinsic stacking faults.


1995 ◽  
Vol 399 ◽  
Author(s):  
Olof Hellman ◽  
Shun-Ichiro Tanaka ◽  
Shigeru Niki ◽  
Paul Fons

ABSTRACTUsing Transmission Electron Microscopy, we examine the defect structure of Cu-rich and In-rich CuInSe2 films grown by Molecular Beam Epitaxy on GaAs (100) substrates. A surprisingly high density of cation sublattice stacking faults on (001) planes are observed in the Cu-rich films. Because these stacking faults are extremely flat and extend thousands of Ångstroms over the surface, and because they are not observed in other, non-Cu-rich films, we argue that they are a consequence of a surface structural change during growth, induced by the excess Cu. Two other types of defects are also observed: near the CuInSe2/GaAs interface, there is a high concentration of dislocations, stacking faults and domain boundaries. In the In-rich films, stacking faults and twin-type defects on {112} planes extend throughout the thickness of the grown film.


2001 ◽  
Vol 7 (S2) ◽  
pp. 556-557
Author(s):  
Y. Yan ◽  
K.M. Jones ◽  
M.M. Al-Jassim

CdTe is a promising photovoltaic material due to its near optimum band gap and high absorption coefficient. Polycrystalline, thin-film CdTe/CdS solar cells have demonstrated an efficiency of 15.8%. High density of extended defects is often found in polycrystalline CdTe films grown by close-spaced sublimation (CSS). So far, most investigations of defects in CdTe have focused on epitaxially grown films, and the reported extended defects are mainly lamellar twins. However, epitaxially grown films generally have a different microstructure compared to CSS grown polycrystalline CdTe thin films. in this paper, we report our study of extended defects in CSSgrown polycrystalline CdTe thin films by high-resolution transmission electron microscopy (HRTEM). We found that the extended defects are mostly lamellar twins and stacking faults. The stacking faults always propagate across the grains, without ending at a partial dislocation inside the grains.


1985 ◽  
Vol 46 ◽  
Author(s):  
C.H. Carter ◽  
J.A. Edmond ◽  
J.W. Palmour ◽  
J. Ryu ◽  
H.J. Kim ◽  
...  

AbstractTechniques have been developed at NCSU for fabricating cross-sectional transmission electron microscopy (XTEM) foils from monocrystalline beta silicon carbide thin films grown by chemical vapor deposition. The results of the TEM observations are utilized to discern the efficacy of the various processing parameters in terms of film quality and defect structure as well as oxidation, ion implantation and annealing procedures.


1980 ◽  
Vol 2 ◽  
Author(s):  
F. A. Ponce ◽  
T. Yamashita ◽  
R. H. Bube ◽  
R. Sinclair

ABSTRACTThe defect structure of cadmium telluride has been investigated using high resolution transmission electron microscopy. The variation of the TEM images with the defocus value is discussed, and defect symmetry considerations are used to correlate the image contrast characteristics with the lattice struc ture. Experimental micrographs of stacking faults and dislocations in the structure are analyzed.


1983 ◽  
Vol 31 ◽  
Author(s):  
Thao A. Nguyen ◽  
Linn W. Hobbs

ABSTRACTThe defect structures of Fe9S10 have been studied by high-resolution transmission electron microscopy. Lattice images of the 3C and 4C superstructures and at least one other phase, which has not been previously reported, were observed. It has been found that the 4C superstructure transforms into the 3C superstructure rather than the MC phase as previously suggested. Intrinsic stacking faults in the sulfur sublattice and two different types of vacancy-ordering antiphase domains were also observed. Evidence from optical diffratograms of areas containing these defects suggests that complex features in the electron diffraction pattern may be artifactual.


Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.


Author(s):  
C. Ewins ◽  
J.R. Fryer

The preparation of thin films of organic molecules is currently receiving much attention because of the need to produce good quality thin films for molecular electronics. We have produced thin films of the polycyclic aromatic, perylene C10H12 by evaporation under high vacuum onto a potassium chloride (KCl) substrate. The role of substrate temperature in determining the morphology and crystallography of the films was then investigated by transmission electron microscopy (TEM).The substrate studied was the (001) face of a freshly cleaved crystal of KCl. The temperature of the KCl was controlled by an electric heater or a cold finger. The KCl was heated to 200°C under a vacuum of 10-6 torr and allowed to cool to the desired temperature. The perylene was then evaporated over a period of one minute from a molybdenum boat at a distance of 10cm from the KCl. The perylene thin film was then backed with an amorphous layer of carbon and floated onto copper microscope grids.


Author(s):  
J. T. Sizemore ◽  
D. G. Schlom ◽  
Z. J. Chen ◽  
J. N. Eckstein ◽  
I. Bozovic ◽  
...  

Investigators observe large critical currents for superconducting thin films deposited epitaxially on single crystal substrates. The orientation of these films is often characterized by specifying the unit cell axis that is perpendicular to the substrate. This omits specifying the orientation of the other unit cell axes and grain boundary angles between grains of the thin film. Misorientation between grains of YBa2Cu3O7−δ decreases the critical current, even in those films that are c axis oriented. We presume that these results are similar for bismuth based superconductors and report the epitaxial orientations and textures observed in such films.Thin films of nominally Bi2Sr2CaCu2Ox were deposited on MgO using molecular beam epitaxy (MBE). These films were in situ grown (during growth oxygen was incorporated and the films were not oxygen post-annealed) and shuttering was used to encourage c axis growth. Other papers report the details of the synthesis procedure. The films were characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM).


Author(s):  
A.C. Daykin ◽  
C.J. Kiely ◽  
R.C. Pond ◽  
J.L. Batstone

When CoSi2 is grown onto a Si(111) surface it can form in two distinct orientations. A-type CoSi2 has the same orientation as the Si substrate and B-type is rotated by 180° degrees about the [111] surface normal.One method of producing epitaxial CoSi2 is to deposit Co at room temperature and anneal to 650°C.If greater than 10Å of Co is deposited then both A and B-type CoSi2 form via a number of intermediate silicides .The literature suggests that the co-existence of A and B-type CoSi2 is in some way linked to these intermediate silicides analogous to the NiSi2/Si(111) system. The phase which forms prior to complete CoSi2 formation is CoSi. This paper is a crystallographic analysis of the CoSi2/Si(l11) bicrystal using a theoretical method developed by Pond. Transmission electron microscopy (TEM) has been used to verify the theoretical predictions and to characterise the defect structure at the interface.


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