Chemical Origin of the Grain Boundary Carrier Recombination in Silicon Bicrystals

1985 ◽  
Vol 59 ◽  
Author(s):  
F. Battistella ◽  
A. Rocher ◽  
A. George
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Direct Relationship ◽  
Minority Carrier ◽  
Neutral Atmosphere ◽  
X Ray ◽  
Heterogeneous Recombination ◽  
Carrier Recombination ◽  
Transmission Electron

ABSTRACTThe minority carrier recombination related to grain boundaries is studied by the SEM/EBIC technique. The specimens investigated are silicon bicrystals obtained by the Czochralski pulling process. The specimens are heated for 2 hours at 750°C in a neutral atmosphere. Heterogeneous recombination of the grain boundaries is then observed.X-Ray topography and Transmission Electron Microscopy (TEM) have been performed to determine the origin of the heterogeneous recombination. A direct relationship between the local recombination along the grain boundary and the precipitates localized at the interface has been established. The chemical origin of the precipitates is discussed.

In-Plane Grain Boundary Effects on the Transport Properties of La0.7Sr0.3MnO3-δ Thin Films

1997 ◽  
Vol 494 ◽  
Author(s):  
J. Y. Gu ◽  
S. B. Ogale ◽  
K. Ghosh ◽  
T. Venkatesan ◽  
R. Ramesh ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Effects ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Low Field ◽  
Grain Structures ◽  
Transmission Electron

ABSTRACTC-axis oriented La0.7Sr0.3MnO3.δ (LSMO) films were fabricated on the top of SrTiO3/YBa2Cu3O7 grown on MgO(001) substrates. From x-ray φ-scan and planar transmission electron microscopy measurements, the LSMO layer in the LSMO/SrTiO3/YBa2Cu3O7/MgO heterostructure is found to have coherent in-plane grain boundaries with a predominance of 45° rotations (between [100] and [110] grains) in addition to the cube-on-cube epitaxial relationship. Also, epitaxial LSMO/Bi4Ti3O12/LaAl03 (001) and c-axis textured LSMO/Bi4Ti3O12/SiO2/Si(001) with random in-plane grain boundaries are introduced as the counterparts for comparison. The resistivity and magnetoresistance (MR) of LSMO layer were measured and compared in these three different heterostructures. The low field MR at low temperature shows a dramatic dependence on the nature of the grain boundary. An attempt is made to interpret these results on the basis of correlation between the magnetic properties and grain structures.

Grain-Boundary Segregation and Phase-Separation Mechanism in Yttria-Stabilized Tetragonal Zirconia Polycrystal

2011 ◽  
Vol 484 ◽  
pp. 82-88
Author(s):  
Koji Matsui ◽  
Hidehiro Yoshida ◽  
Yuichi Ikuhara
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
Cubic Phase ◽  
Phase Boundaries ◽  
Transmission Electron ◽  
Sintering Condition

Microstructure development during sintering in 3 mol% Y2O3-stabilized tetragonal ZrO2 polycrystal (Y-TZP) was systematically investigated in two sintering conditions: (a) 1100-1650°C for 2 h and (b) 1300°C for 0-50 h. In the sintering condition (a), the density and grain size in Y-TZP increased with the increasing sintering temperature. Scanning transmission electron microscopy (STEM) and nanoprobe X-ray energy dispersive spectroscopy (EDS) measurements revealed that the Y3+ ion distribution was nearly homogeneous up to 1300°C, i.e., most of grains were the tetragonal phase, but cubic-phase regions with high Y3+ ion concentration were clearly formed in grain interiors adjacent to the grain boundaries at 1500°C. High-resolution transmission electron microscopy (HRTEM) and nanoprobe EDS measurements revealed that no amorphous or second phase is present along the grain-boundary faces, and Y3+ ions segregated not only along the tetragonal-tetragonal phase boundaries but also along tetragonal-cubic phase boundaries over a width below about 10 nm, respectively. These results indicate that the cubic-phase regions are formed from the grain boundaries and/or the multiple junctions in which Y3+ ions segregated. We termed this process a “grain boundary segregation-induced phase transformation (GBSIPT)” mechanism. In the sintering condition (b), the density was low and the grain-growth rate was much slow. In the specimen sintered at 1300°C for 50 h, the cubic-phase regions were clearly formed in the grain interiors adjacent to the grain boundaries. This behavior shows that the cubic-phase regions were formed without grain growth, which can be explained by the GBSIPT model.

A Novel Low-Temperature-Fired Multifunctional Varistor-Magnetic Ferrite Materials

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000641-000649
Author(s):  
Li-Then Mei ◽  
Hsing-I Hsiang ◽  
Hui-Wen Ye
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Grain Boundary ◽  
Schottky Barriers ◽  
Energy Dispersion Spectroscopy ◽  
X Ray ◽  
Transmission Electron ◽  
Donor Dopant ◽  
Type Semiconductor ◽  
The Relationship

A novel low temperature-fired (950°C) multifunctional varistor-magnetic ferrite materials can be obtained by adding V2O5 into CuCr0.2Fe1.8O4 ferrites. The relationship between the grain-boundary composition and varistor properties were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersion spectroscopy (EDS), and X-ray photoelectric spectroscopy (XPS). The addition of V2O5 can effectively reduce the sintering temperature of CuCr0.2Fe1.8O4 ferrites to temperatures of lower than 950°C. Moreover, the V5+ ions occupied the octahedral site of spinel structure and acted as donor dopant, which resulted in the semiconductive grain. The copper-rich observation at the grain boundary based on the TEM and EDS results implied that copper oxide would possibly develop at the grain boundary as the acceptor state, forming double Schottky barriers with the n-type semiconductor grains.

Grain Boundary Transformations in Bi-Doped Copper

1991 ◽  
Vol 238 ◽  
Author(s):  
Elsie C. Urdaneta ◽  
David E. Luzzi ◽  
Charles J. McMahon
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Treatment Time ◽  
High Resolution Electron Microscopy ◽  
Transmission Electron ◽  
Resolution Electron

ABSTRACTBismuth-induced grain boundary faceting in Cu-12 at ppm Bi polycrystals was studied using transmission electron microscopy (TEM). The population of faceted grain boundaries in samples aged at 600°C was observed to increase with heat treatment time from 15min to 24h; aging for 72h resulted in de-faceting, presumably due to loss of Bi from the specimen. The majority of completely faceted boundaries were found between grains with misorientation Σ=3. About 65% of the facets of these boundaries were found to lie parallel to crystal plane pairs of the type {111}1/{111]2- The significance of these findings in light of recent high resolution electron microscopy experiments is discussed.

Grain Boundary Segregation-Induced Phase Transformation and Grain Growth in Y2O3-Stabilized ZrO2 Polycrystals

2014 ◽  
Vol 616 ◽  
pp. 8-13
Author(s):  
Koji Matsui ◽  
Hidehiro Yoshida ◽  
Yuichi Ikuhara
Keyword(s):  
Electron Microscopy ◽  
Phase Transformation ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Grain Growth ◽  
Boundary Segregation ◽  
Growth Behavior ◽  
Grain Boundary Segregation ◽  
Transmission Electron ◽  
Grain Growth Behavior

We systematically investigated the phase transformation and grain-growth behaviors during sintering in 2 and 3 mol% Y2O3-stabilized tetragonal ZrO2 (2Y and 3Y) and 8 mol% Y2O3-stabilized cubic ZrO2 polycrystals (8Y). In particular, grain-boundary segregation and grain-interior distribution of Y3+ ions were examined by high-resolution transmission electron microscopy (HRTEM)- and scanning transmission electron microscopy (STEM)-nanoprobe X-ray energy dispersive spectroscopy (EDS) techniques. Above 1200°C, grain growth during sintering in 8Y was much faster than that in 2Y and 3Y. In the grain boundaries in these specimens, amorphous layers did not present; however, Y3+ ions segregated at the grain boundaries over a width of about 10 nm. The amount of segregated Y3+ ions in 8Y was significantly less than in 2Y and 3Y. This indicates that the amount of segregated Y3+ ions is related to grain growth behavior; i.e., an increase in segregated Y3+ ions retards grain growth. Therefore, grain-growth behavior during sintering can be reasonably explained by the solute-drag mechanism of Y3+ ions segregating along the grain boundary. In 2Y and 3Y, the cubic-phase regions were formed in grain interiors adjacent to the grain boundaries and/or the multiple junctions in which Y3+ ions segregated, which can be explained by a grain boundary segregation-induced phase transformation (GBSIPT) mechanism.

Preparation and characteristics of 90° rotated biepitaxial Fe3O4 thin films

2002 ◽  
Vol 17 (8) ◽  
pp. 1985-1991 ◽  
Author(s):  
Hiroshi Matsuda ◽  
Hiroshi Sakakima ◽  
Hideaki Adachi ◽  
Akihiro Odagawa ◽  
Kentaro Setsune
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Electron Diffraction ◽  
Grain Boundary ◽  
Seed Layer ◽  
Tunneling Magnetoresistance ◽  
X Ray ◽  
Transmission Electron

In-plane 90° rotated biepitaxial Fe3O4 thin films have been successfully prepared onto MgO (110) substrates using a CeO2 seed layer and their microstructure, electric, and magnetic properties were investigated. From the x-ray φ-scan measurements, the in-plane epitaxial relations were determined as 〈110〉Fe3O4//〈110〉MgO and 〈001〉Fe3O4//〈001〉MgO for the no-seeded Fe3O4 layer, and 〈001〉Fe3O4//〈110〉MgO and 〈110〉Fe3O4//〈001〉MgO for the CeO2 (110) seeded Fe3O4 layer. The CeO2 seed layer was found to rotate the upper Fe3O4 lattice at 90° upon normal axis to the layer against the no-seeded Fe3O4. The transmission electron microscopy and electron diffraction analyses revealed that the transition region of the biepitaxial Fe3O4 boundary between CeO2-seeded and no-seeded portions consisted of columnarlike polycrystalline grains. The Fe 3O4 films exhibited single-crystallinelike electric and magnetic properties, however, substantial spin-dependent-tunneling magnetoresistance across the 90° grain boundary was not observed even in the antiparallel situation for each Fe3O4 portion.

Research on Solution and Aging Treatment of Mg-7Zn-3Al Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 247-250
Author(s):  
Jing Zhang ◽  
Fu Sheng Pan ◽  
Ru Lin Zuo
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Aging Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Quantitative Image ◽  
The Matrix

Effect of solution and aging treatment on the microstructure of Mg-7Zn-3Al alloy is studied by using optical microscopy, scanning electron microscopy, X-ray diffraction, transmission electron microscopy and quantitative image analysis. The results show that the as-aged microstructure is composed of α-Mg matrix, grain boundary τ (Mg32(Al,Zn)49 ) phase, and fine dispersed τ particles inside the grain. The solution degree has significant effects on the formation, morphology, and size of the grain boundary τ phase. The volume fraction and the size of the undissolved eutectic τ phase decrease with the increase of solution time treated at 325°C. Through sufficient solution treatment, discontinuous eutectic τ phase retains fine strip morphology after aging, in contrast to the microstructure in sample undergone insufficient solution which manifests as-cast feature, while at the same time nano-sized particles precipitate out from the matrix. The precipitates display paralleled short bar, having certain orientation relationship with the matrix.

The Role of Transmission Electron Microscopy in Characterizing the Nature and Behavior of Grain Boundaries

1971 ◽  
Vol 29 ◽  
pp. 102-103
Author(s):  
L. E. Murr
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Degrees Of Freedom ◽  
Effective Means ◽  
Average Energy ◽  
Interfacial Free Energy ◽  
Transmission Electron ◽  
And Behavior

Grain boundaries represent the single, most dominant imperfection in structural materials of engineering and industrial importance, and are a controlling factor in the strength of materials. Transmission electron microscopy, combined with the ability to gain direct crystallographic information from associated selected-area electron diffraction patterns, represents perhaps the most effective means for the investigation of the nature and behavior of grain boundaries in solids.Any segment of a grain boundary has associated with it five degrees of freedom. The electron microscope has the capability to characterize these degrees of freedom and to uniquely define the geometrical and crystallographic nature of a grain boundary. In addition, once the true geometry of intersecting grain boundaries or grain boundaries intersecting with other interfaces is determined, interfacial free energy ratios can be calculated from which the average energy associated with particular types of interfaces can be determined.

Nano-probe microanalysis of grain boundary chemistry in YBa2Cu4O8 and its relationship to weak-link behavior

1993 ◽  
Vol 51 ◽  
pp. 598-599
Author(s):  
Z.L. Wang ◽  
J. Brynestad ◽  
D.M. Kroeger ◽  
Y.R. Sun ◽  
J.R. Thompson ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Weak Link ◽  
Oxygen Deficiency ◽  
High Temperature Superconductors ◽  
Cation Composition ◽  
X Ray ◽  
Transmission Electron ◽  
Boundary Chemistry ◽  
Electron Energy Loss

Weak-link behavior in high temperature superconductors limits bulk applications of polycrystalline high Tc compounds. Possible sources of the effect include grain boundary (GB) disorder, microcracks and nonstoichiometric material at grain boundaries. Recently, electron energy-loss spectroscopy (EELS) studies of YBa2Cu3O7-x (Y123) have shown that grain boundary oxygen deficiency is correlated with the crystallographic misorientations of between the Y123 grains. Studies of grain boundary chemistry in YBa2Cu4O8 (Y124) by nano-probe energy dispersive X-ray spectroscopy (EDS) and EELS are reported in this paper. Transmission electron microscopy (TEM) studies were performed at 100 kV in a Philips EM400 TEM/STEM equipped with a field emission gun (FEG), which generates an electron probe smaller than 2 nm in diameter. The cation composition was determined by EDS and the O:Ba composition was determined using EELS. Kikuchi patterns were recorded from both sides of the grain boundaries to determine the misorientation of the two adjacent grains.The observation of a pre-edge peak (Fig. 1) near the oxygen K ionization edge (O K) is related to the hole states produced by the O 2p state and Cu 3d states.

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