| |
Records |
|
Author |
Verleysen, E.; Bender, H.; Richard, O.; Schryvers, D.; Vandervorst, W. |
| |
Title |
Compositional characterization of nickel silicides by HAADF-STEM imaging |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Journal of materials science |
Abbreviated Journal |
J Mater Sci |
| |
Volume |
46 |
Issue |
7 |
Pages |
2001-2008 |
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| |
Abstract |
A methodology for the quantitative compositional characterization of nickel silicides by high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) imaging is presented. HAADF-STEM images of a set of nickel silicide reference samples Ni3Si, Ni31Si12, Ni2Si, NiSi and NiSi2 are taken at identical experimental conditions. The correlation between sample thickness and HAADF-STEM intensity is discussed. In order to quantify the relationship between the experimental Z-contrast intensities and the composition of the analysed layers, the ratio of the HAADF-STEM intensity to the sample thickness or to the intensity of the silicon substrate is determined for each nickel silicide reference sample. Diffraction contrast is still detected on the HAADF-STEM images, even though the detector is set at the largest possible detection angle. The influence on the quantification results of intensity fluctuations caused by diffraction contrast and channelling is examined. The methodology is applied to FUSI gate devices and to horizontal TFET devices with different nickel silicides formed on source, gate and drain. It is shown that, if the elements which are present are known, this methodology allows a fast quantitative 2-dimensional compositional analysis. |
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Address |
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Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
London |
Editor |
|
| |
Language |
|
Wos |
000286633000002 |
Publication Date |
2011-01-06 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
0022-2461;1573-4803; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
2.599 |
Times cited |
1 |
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 2.599; 2011 IF: 2.015 |
| |
Call Number  |
UA @ lucian @ c:irua:88950 |
Serial |
446 |
| Permanent link to this record |
| |
|
| |
|
Author |
Lindner, H.; Loper, K.H.; Hahn, D.W.; Niemax, K. |
| |
Title |
The influence of laser-particle interaction in laser induced breakdown spectroscopy and laser ablation inductively coupled plasma spectrometry |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Spectrochimica acta: part B : atomic spectroscopy |
Abbreviated Journal |
Spectrochim Acta B |
| |
Volume |
66 |
Issue |
2 |
Pages |
179-185 |
| |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| |
Abstract |
Particles produced by previous laser shots may have significant influence on the analytical signal in laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma (LA-ICP) spectrometry if they remain close to the position of laser sampling. The effects of these particles on the laser-induced breakdown event are demonstrated in several ways. LIBS-experiments were conducted in an ablation cell at atmospheric conditions in argon or air applying a dual-pulse arrangement with orthogonal pre-pulse, i.e., plasma breakdown in a gas generated by a focussed laser beam parallel and close to the sample surface followed by a delayed crossing laser pulse in orthogonal direction which actually ablates material from the sample and produces the LIBS plasma. The optical emission of the LIBS plasma as well as the absorption of the pre-pulse laser was measured. In the presence of particles in the focus of the pre-pulse laser, the plasma breakdown is affected and more energy of the pre-pulse laser is absorbed than without particles. As a result, the analyte line emission from the LIBS plasma of the second laser is enhanced. It is assumed that the enhancement is not only due to an increase of mass ablated by the second laser but also to better atomization and excitation conditions favored by a reduced gas density in the pre-pulse plasma. Higher laser pulse frequencies increase the probability of particle-laser interaction and, therefore, reduce the shot-to-shot line intensity variation as compared to lower particle loadings in the cell. Additional experiments using an aerosol chamber were performed to further quantify the laser absorption by the plasma in dependence on time both with and without the presence of particles. The overall implication of laser-particle interactions for LIBS and LA-ICP-MS/OES are discussed. |
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Address |
|
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Corporate Author |
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Thesis |
|
| |
Publisher |
|
Place of Publication |
Oxford |
Editor |
|
| |
Language |
|
Wos |
000289328900012 |
Publication Date |
2011-01-20 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
0584-8547; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
3.241 |
Times cited |
12 |
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 3.241; 2011 IF: 2.876 |
| |
Call Number |
UA @ lucian @ c:irua:89008 |
Serial |
1627 |
| Permanent link to this record |
| |
|
| |
|
Author |
Verberck, B.; Tarakina, N.V. |
| |
Title |
Tubular fullerenes inside carbon nanotubes : optimal molecular orientation versus tube radius |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
European physical journal : B : condensed matter and complex systems |
Abbreviated Journal |
Eur Phys J B |
| |
Volume |
80 |
Issue |
3 |
Pages |
355-362 |
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
| |
Abstract |
We present an investigation of the orientations and positions of tubular fullerene molecules (C90, ..., C200) encapsulated in single-walled carbon nanotubes (SWCNT), a series of so-called fullerene nanopeapods. We find that increasing the tube radius leads to the following succession of energetically stable regimes: (1) lying molecules positioned on the tube's long axis; (2) tilted molecules on the tube's long axis; and (3) lying molecules shifted away from the tube's long axis. As opposed to C70 and C80 molecules encapsulated in a SWCNT, standing orientations do not develop. Our results are relevant for the possible application of molecular-orientation-dependent electronic properties of fullerene nanopeapods, and also for the interpretation of future experiments on double-walled carbon nanotube formation by annealing fullerene peapod systems. |
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Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
Berlin |
Editor |
|
| |
Language |
|
Wos |
000289576200010 |
Publication Date |
2011-03-14 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1434-6028;1434-6036; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
1.461 |
Times cited |
10 |
Open Access |
|
| |
Notes |
; This work was financially supported by the Research Foundation – Flanders (FWO-VI). B.V. is a Postdoctoral Fellow of the Research Foundation – Flanders (FWO-VI). ; |
Approved |
Most recent IF: 1.461; 2011 IF: 1.534 |
| |
Call Number |
UA @ lucian @ c:irua:89286 |
Serial |
3738 |
| Permanent link to this record |
| |
|
| |
|
Author |
Vandenberghe, W.G.; Sorée, B.; Magnus, W.; Groeseneken, G.; Fischetti, M.V. |
| |
Title |
Impact of field-induced quantum confinement in tunneling field-effect devices |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
| |
Volume |
98 |
Issue |
14 |
Pages |
143503,1-143503,3 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| |
Abstract |
Being the working principle of a tunnel field-effect transistor, band-to-band tunneling is given a rigorous quantum mechanical treatment to incorporate confinement effects, multiple electron and hole valleys, and interactions with phonons. The model reveals that the strong band bending near the gate dielectric, required to create short tunnel paths, results in quantization of the energy bands. Comparison with semiclassical models reveals a big shift in the onset of tunneling. The effective mass difference of the distinct valleys is found to reduce the subthreshold swing steepness. |
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Address |
|
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Corporate Author |
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Thesis |
|
| |
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
| |
Language |
|
Wos |
000289297800074 |
Publication Date |
2011-04-06 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
3.411 |
Times cited |
76 |
Open Access |
|
| |
Notes |
; The authors acknowledge Anne Verhulst for useful discussions. William Vandenberghe gratefully acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). This work was supported by IMEC's Industrial Affiliation Program. ; |
Approved |
Most recent IF: 3.411; 2011 IF: 3.844 |
| |
Call Number |
UA @ lucian @ c:irua:89297 |
Serial |
1559 |
| Permanent link to this record |
| |
|
| |
|
Author |
Liu, C.-Y.; Berdiyorov, G.R.; Milošević, M.V. |
| |
Title |
Vortex states in layered mesoscopic superconductors |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
| |
Volume |
83 |
Issue |
10 |
Pages |
104524-104524,10 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| |
Abstract |
Within the Ginzburg-Landau theory, we study the vortex structures in three-dimensional anisotropic mesoscopic superconductors in the presence of a uniform magnetic field. Anisotropy is included through varied Tc in different layers of the sample and leads to distinct differences in the vortex states and their free energy. Several unconventional states are found, some comprising vortex clusters or exhibiting asymmetry. In a tilted magnetic field, we found second-order transitions between different vortex states, although vortex entry is generally a first-order transition in mesoscopic samples. In multilayered samples the kinked vortex strings are formed owing to the competing interactions of vortices with Meissner currents and the weak-link boundaries. The length and deformation of vortex fragments are determined solely by the inclination and strength of applied magnetic field, and this lock-in does not depend on the degree of anisotropy between the superconducting layers. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
|
Editor |
|
| |
Language |
|
Wos |
000288998200003 |
Publication Date |
2011-03-31 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
3.836 |
Times cited |
22 |
Open Access |
|
| |
Notes |
; ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
| |
Call Number |
UA @ lucian @ c:irua:89375 |
Serial |
3888 |
| Permanent link to this record |
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|
| |
|
Author |
Li, B.; Peeters, F.M. |
| |
Title |
Tunable optical Aharonov-Bohm effect in a semiconductor quantum ring |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
| |
Volume |
83 |
Issue |
11 |
Pages |
115448-115448,13 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| |
Abstract |
By applying an electric field perpendicular to a semiconductor quantum ring we show that it is possible to modify the single particle wave function between quantum dot (QD)-like and ring-like. The constraints on the geometrical parameters of the quantum ring to realize such a transition are derived. With such a perpendicular electric field we are able to tune the Aharanov-Bohm (AB) effect for both the single particle and for excitons. The tunability is in both the strength of the AB effect as well as in its periodicity. We also investigate the strain induce potential inside the self-assembled quantum ring and the effect of the strain on the AB effect. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
|
Editor |
|
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Language |
|
Wos |
000288855200012 |
Publication Date |
2011-03-28 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
3.836 |
Times cited |
25 |
Open Access |
|
| |
Notes |
; This work was supported by the EU-NoE: SANDiE, the Flemish Science Foundation (FWO-Vl), the Interuniversity Attraction Poles, Belgium State, Belgium Science Policy, and IMEC, vzw collaborative project. We are grateful to Prof. M. Tadic and Dr. Fei Ding for stimulating discussions. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
| |
Call Number |
UA @ lucian @ c:irua:89376 |
Serial |
3744 |
| Permanent link to this record |
| |
|
| |
|
Author |
Matulis, A.; Masir, M.R.; Peeters, F.M. |
| |
Title |
Application of optical beams to electrons in graphene |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
| |
Volume |
83 |
Issue |
11 |
Pages |
115458-115458,7 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| |
Abstract |
The technique of beam optics is applied to the description of the wave function of Dirac electrons. This approach is illustrated by considering electron transmission through simple nonhomogeneous structures, such as flat and bent p-n junctions and superlattices. We found that a convex p-n junction compresses the beam waist, while a concave interface widens it without loosing its focusing properties. At a flat p-n junction the waist of the transmitted Gaussian beam can be narrowed or widened, depending on the angle of incidence. A general condition is derived for the occurrence of beam collimation in a superlattice which is less stringent than previous discussed. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
|
Editor |
|
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Language |
|
Wos |
000288896400013 |
Publication Date |
2011-03-29 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
3.836 |
Times cited |
13 |
Open Access |
|
| |
Notes |
; This research was supported by the Flemish Science Foundation (Grant No. FWO-Vl), by the Belgian Science policy (IAP), and (in part) by the Lithuanian Science Council under project No. MIP-79/2010. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
| |
Call Number |
UA @ lucian @ c:irua:89377 |
Serial |
142 |
| Permanent link to this record |
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| |
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Author |
Zeng, Y.I.; Menghini, M.; Li, D.Y.; Lin, S.S.; Ye, Z.Z.; Hadermann, J.; Moorkens, T.; Seo, J.W.; Locquet, J.-P.; van Haesendonck, C. |
| |
Title |
Unexpected optical response of single ZnO nanowires probed using controllable electrical contacts |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Physical chemistry, chemical physics |
Abbreviated Journal |
Phys Chem Chem Phys |
| |
Volume |
13 |
Issue |
15 |
Pages |
6931-6935 |
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| |
Abstract |
Relying on combined electron-beam lithography and lift-off methods Au/Ti bilayer electrical contacts were attached to individual ZnO nanowires (NWs) that were grown by a vapor phase deposition method. Reliable Schottky-type as well as ohmic contacts were obtained depending on whether or not an ion milling process was used. The response of the ZnO NWs to ultraviolet light was found to be sensitive to the type of contacts. The intrinsic electronic properties of the ZnO NWs were studied in a field-effect transistor configuration. The transfer characteristics, including gate threshold voltage, hysteresis and operational mode, were demonstrated to unexpectedly respond to visible light. The origin of this effect could be accounted for by the presence of point defects in the ZnO NWs. |
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Address |
|
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Cambridge |
Editor |
|
| |
Language |
|
Wos |
000288951000019 |
Publication Date |
2011-03-14 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1463-9076;1463-9084; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
4.123 |
Times cited |
7 |
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 4.123; 2011 IF: 3.573 |
| |
Call Number |
UA @ lucian @ c:irua:89378 |
Serial |
3807 |
| Permanent link to this record |
| |
|
| |
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Author |
Hellmuth, K.H.; Siitari-Kaupi, M.; Rauhala, E.; Johansson, B.; Zilliacus, R.; Gijbels, R.; Adriaens, A. |
| |
Title |
Reactions of high FeO-olivine rock with groundwater and redox-sensitive elements studied by surface-analytical methods and autoradiography |
Type |
P1 Proceeding |
| |
Year |
1994 |
Publication |
Materials Research Society symposium proceedings |
Abbreviated Journal |
|
| |
Volume |
333 |
Issue |
|
Pages |
947-953 |
| |
Keywords |
P1 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| |
Abstract |
|
| |
Address |
|
| |
Corporate Author |
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Thesis |
|
| |
Publisher |
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Place of Publication |
Wuhan |
Editor |
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| |
Language |
|
Wos |
A1994BA13E00112 |
Publication Date |
0000-00-00 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
0272-9172 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
|
Times cited |
6 |
Open Access |
|
| |
Notes |
|
Approved |
|
| |
Call Number |
UA @ lucian @ c:irua:8939 |
Serial |
2821 |
| Permanent link to this record |
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|
| |
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Author |
Katti, G.; Stucchi, M.; Velenis, D.; Sorée, B.; de Meyer, K.; Dehaene, W. |
| |
Title |
Temperature-dependent modeling and characterization of through-silicon via capacitance |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
IEEE electron device letters |
Abbreviated Journal |
Ieee Electr Device L |
| |
Volume |
32 |
Issue |
4 |
Pages |
563-565 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| |
Abstract |
A semianalytical model of the through-silicon via (TSV) capacitance for elevated operating temperatures is derived and verified with electrical measurements. The effect of temperature on the increase in TSV capacitance over different technology parameters is explored, and it is shown that higher oxide thickness reduces the impact of temperature rise on TSV capacitance, while with low doped substrates, which are instrumental for reducing the TSV capacitance, the sensitivity of TSV capacitance to temperature is large and cannot be ignored. |
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Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
|
Editor |
|
| |
Language |
|
Wos |
000288664800045 |
Publication Date |
2011-03-04 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
0741-3106;1558-0563; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
3.048 |
Times cited |
27 |
Open Access |
|
| |
Notes |
; ; |
Approved |
Most recent IF: 3.048; 2011 IF: 2.849 |
| |
Call Number |
UA @ lucian @ c:irua:89402 |
Serial |
3498 |
| Permanent link to this record |
| |
|
| |
|
Author |
Adriaens, A.; van Nevel, L.; Van 't dack, L.; de Bièvre, P.; Adams, F.; Gijbels, R. |
| |
Title |
The use of surface analysis techniques and isotope mass spectrometry for the study of water-rock interactions of interest in hot-dry rock technology |
Type |
P3 Proceeding |
| |
Year |
1995 |
Publication |
|
Abbreviated Journal |
|
| |
Volume |
|
Issue |
|
Pages |
2541-2544 |
| |
Keywords |
P3 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| |
Abstract |
|
| |
Address |
|
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Corporate Author |
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Thesis |
|
| |
Publisher |
|
Place of Publication |
Auckland |
Editor |
|
| |
Language |
|
Wos |
|
Publication Date |
0000-00-00 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
|
ISBN |
|
Additional Links |
UA library record |
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
| |
Notes |
|
Approved |
no |
| |
Call Number |
UA @ lucian @ c:irua:8942 |
Serial |
3824 |
| Permanent link to this record |
| |
|
| |
|
Author |
Sels, D.; Sorée, B.; Groeseneken, G. |
| |
Title |
Quantum ballistic transport in the junctionless nanowire pinch-off field effect transistor |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Journal of computational electronics |
Abbreviated Journal |
J Comput Electron |
| |
Volume |
10 |
Issue |
1 |
Pages |
216-221 |
| |
Keywords |
A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT) |
| |
Abstract |
In this work we investigate quantum ballistic transport in ultrasmall junctionless and inversion mode semiconducting nanowire transistors within the framework of the self-consistent Schrödinger-Poisson problem. The quantum transmitting boundary method is used to generate open boundary conditions between the active region and the electron reservoirs. We adopt a subband decomposition approach to make the problem numerically tractable and make a comparison of four different numerical approaches to solve the self-consistent Schrödinger-Poisson problem. Finally we discuss the IV-characteristics for small (r≤5 nm) GaAs nanowire transistors. The novel junctionless pinch-off FET or junctionless nanowire transistor is extensively compared with the gate-all-around (GAA) nanowire MOSFET. |
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Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
S.l. |
Editor |
|
| |
Language |
|
Wos |
000300735800021 |
Publication Date |
2011-02-22 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1569-8025;1572-8137; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
1.526 |
Times cited |
12 |
Open Access |
|
| |
Notes |
; ; |
Approved |
Most recent IF: 1.526; 2011 IF: 1.211 |
| |
Call Number |
UA @ lucian @ c:irua:89501 |
Serial |
2772 |
| Permanent link to this record |
| |
|
| |
|
Author |
Cantoro, M.; Klekachev, A.V.; Nourbakhsh, A.; Sorée, B.; Heyns, M.M.; de Gendt, S. |
| |
Title |
Long-wavelength, confined optical phonons in InAs nanowires probed by Raman spectroscopy |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
European physical journal : B : condensed matter and complex systems |
Abbreviated Journal |
Eur Phys J B |
| |
Volume |
79 |
Issue |
4 |
Pages |
423-428 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| |
Abstract |
Strongly confined nano-systems, such as one-dimensional nanowires, feature deviations in their structural, electronic and optical properties from the corresponding bulk. In this work, we investigate the behavior of long-wavelength, optical phonons in vertical arrays of InAs nanowires by Raman spectroscopy. We attribute the main changes in the spectral features to thermal anharmonicity, due to temperature effects, and rule out the contribution of quantum confinement and Fano resonances. We also observe the appearance of surface optical modes, whose details allow for a quantitative, independent estimation of the nanowire diameter. The results shed light onto the mechanisms of lineshape change in low-dimensional InAs nanostructures, and are useful to help tailoring their electronic and vibrational properties for novel functionalities. |
| |
Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
Berlin |
Editor |
|
| |
Language |
|
Wos |
000288120600005 |
Publication Date |
2011-02-03 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1434-6028;1434-6036; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
1.461 |
Times cited |
10 |
Open Access |
|
| |
Notes |
; ; |
Approved |
Most recent IF: 1.461; 2011 IF: 1.534 |
| |
Call Number |
UA @ lucian @ c:irua:89502 |
Serial |
1841 |
| Permanent link to this record |
| |
|
| |
|
Author |
Magnus, W.; Brosens, F.; Sorée, B. |
| |
Title |
Modeling drive currents and leakage currents : a dynamic approach |
Type |
A1 Journal article |
| |
Year |
2009 |
Publication |
Journal of computational electronics |
Abbreviated Journal |
J Comput Electron |
| |
Volume |
8 |
Issue |
3/4 |
Pages |
307-323 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Theory of quantum systems and complex systems |
| |
Abstract |
The dynamics of electrons and holes propagating through the nano-scaled channels of modern semiconductor devices can be seen as a widespread manifestation of non-equilibrium statistical physics and its ruling principles. In this respect both the devices that are pushing conventional CMOS technology towards the final frontiers of Moores law and the upcoming set of alternative, novel nanostructures grounded on entirely new concepts and working principles, provide an almost unlimited playground for assessing physical models and numerical techniques emerging from classical and quantum mechanical non-equilibrium theory. In this paper we revisit the Boltzmann as well as the WignerBoltzmann equation which offers a valuable platform to study transport of charge carriers taking part in drive currents. We focus on a numerical procedure that regained attention recently as an alternative tool to solve the time-dependent Boltzmann equation for inhomogeneous systems, such as the channel regions of field-effect transistors, and we discuss its extension to the WignerBoltzmann equation. Furthermore, we pay attention to the calculation of tunneling leakage currents. The latter typically occurs in nano-scaled transistors when part of the carrier distribution sustaining the drive current is found to tunnel into the gate due the presence of an ultra-thin insulating barrier separating the gate from the channel region. In particular, we discuss the paradox related to the very existence of leakage currents established by electrons occupying quasi-bound states, while the (real) wave functions of the latter cannot carry net currents. Finally, we describe a simple model to resolve the paradox as well as to estimate gate currents provided the local carrier generation rates largely exceed the tunneling rates. |
| |
Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
S.l. |
Editor |
|
| |
Language |
|
Wos |
000208236100009 |
Publication Date |
2009-09-28 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1569-8025;1572-8137; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
1.526 |
Times cited |
4 |
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 1.526; 2009 IF: NA |
| |
Call Number |
UA @ lucian @ c:irua:89503 |
Serial |
2110 |
| Permanent link to this record |
| |
|
| |
|
Author |
Sorée, B.; Magnus, W.; Pourtois, G. |
| |
Title |
Analytical and self-consistent quantum mechanical model for a surrounding gate MOS nanowire operated in JFET mode |
Type |
A1 Journal article |
| |
Year |
2008 |
Publication |
Journal of computational electronics |
Abbreviated Journal |
J Comput Electron |
| |
Volume |
7 |
Issue |
3 |
Pages |
380-383 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| |
Abstract |
We derive an analytical model for the electrostatics and the drive current in a silicon nanowire operating in JFET mode. We show that there exists a range of nanowire radii and doping densities for which the nanowire JFET satisfies reasonable device characteristics. For thin nanowires we have developed a self-consistent quantum mechanical model to obtain the electronic structure. |
| |
Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
S.l. |
Editor |
|
| |
Language |
|
Wos |
000208473800067 |
Publication Date |
2008-02-20 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1569-8025;1572-8137; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
1.526 |
Times cited |
70 |
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 1.526; 2008 IF: NA |
| |
Call Number |
UA @ lucian @ c:irua:89504 |
Serial |
107 |
| Permanent link to this record |
| |
|
| |
|
Author |
Pourghaderi, M.A.; Magnus, W.; Sorée, B.; de Meyer, K.; Meuris, M.; Heyns, M. |
| |
Title |
General 2D Schrödinger-Poisson solver with open boundary conditions for nano-scale CMOS transistors |
Type |
A1 Journal article |
| |
Year |
2008 |
Publication |
Journal of computational electronics |
Abbreviated Journal |
J Comput Electron |
| |
Volume |
7 |
Issue |
4 |
Pages |
475-484 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| |
Abstract |
Employing the quantum transmitting boundary (QTB) method, we have developed a two-dimensional Schrödinger-Poisson solver in order to investigate quantum transport in nano-scale CMOS transistors subjected to open boundary conditions. In this paper we briefly describe the building blocks of the solver that was originally written to model silicon devices. Next, we explain how to extend the code to semiconducting materials such as germanium, having conduction bands with energy ellipsoids that are neither parallel nor perpendicular to the channel interfaces or even to each other. The latter introduces mixed derivatives in the 2D effective mass equation, thereby heavily complicating the implementation of open boundary conditions. We present a generalized quantum transmitting boundary method that mainly leans on the completeness of the eigenstates of the effective mass equation. Finally, we propose a new algorithm to calculate the chemical potentials of the source and drain reservoirs, taking into account their mutual interaction at high drain voltages. As an illustration, we present the potential and carrier density profiles obtained for a (111) Ge NMOS transistor as well as the ballistic current characteristics. |
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Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
S.l. |
Editor |
|
| |
Language |
|
Wos |
000209032500002 |
Publication Date |
2008-09-02 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1569-8025;1572-8137; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
1.526 |
Times cited |
3 |
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 1.526; 2008 IF: NA |
| |
Call Number |
UA @ lucian @ c:irua:89505 |
Serial |
1322 |
| Permanent link to this record |
| |
|
| |
|
Author |
Sorée, B.; Magnus, W. |
| |
Title |
Quantized conductance without reservoirs : method of the nonequilibrium statistical operator |
Type |
A1 Journal article |
| |
Year |
2007 |
Publication |
Journal of computational electronics |
Abbreviated Journal |
J Comput Electron |
| |
Volume |
6 |
Issue |
1/3 |
Pages |
255-258 |
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
| |
Abstract |
We introduce a generalized non-equilibrium statistical operator (NSO) to study a current-carrying system. The NSO is used to derive a set of quantum kinetic equations based on quantum mechanical balance equations. The quantum kinetic equations are solved self-consistently together with Poissons equation to solve a general transport problem. We show that these kinetic equations can be used to rederive the Landauer formula for the conductance of a quantum point contact, without any reference to reservoirs at different chemical potentials. Instead, energy dissipation is taken into account explicitly through the electron-phonon interaction. We find that both elastic and inelastic scattering are necessary to obtain the Landauer conductance. |
| |
Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
S.l. |
Editor |
|
| |
Language |
|
Wos |
000208473600062 |
Publication Date |
2007-01-17 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1569-8025;1572-8137; |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| |
Impact Factor |
1.526 |
Times cited |
|
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 1.526; 2007 IF: NA |
| |
Call Number |
UA @ lucian @ c:irua:89506 |
Serial |
2769 |
| Permanent link to this record |
| |
|
| |
|
Author |
Verhulst, A.; Sorée, B.; Leonelli, D.; Vandenberghe, W.G.; Groeseneken, G. |
| |
Title |
Modeling the single-gate, double-gate, and gate-all-around tunnel field-effect transistor |
Type |
A1 Journal article |
| |
Year |
2010 |
Publication |
Journal Of Applied Physics |
Abbreviated Journal |
J Appl Phys |
| |
Volume |
107 |
Issue |
2 |
Pages |
024518,1-024518,8 |
| |
Keywords |
A1 Journal article; Electron Microscopy for Materials Science (EMAT); |
| |
Abstract |
Tunnel field-effect transistors (TFETs) are potential successors of metal-oxide-semiconductor FETs because scaling the supply voltage below 1 V is possible due to the absence of a subthreshold-swing limit of 60 mV/decade. The modeling of the TFET performance, however, is still preliminary. We have developed models allowing a direct comparison between the single-gate, double-gate, and gate-all-around configuration at high drain voltage, when the drain-voltage dependence is negligible, and we provide improved insight in the TFET physics. The dependence of the tunnel current on device parameters is analyzed, in particular, the scaling with gate-dielectric thickness, channel thickness, and dielectric constants of gate dielectric and channel material. We show that scaling the gate-dielectric thickness improves the TFET performance more than scaling the channel thickness and that improvements are often overestimated. There is qualitative agreement between our model and our experimental data. |
| |
Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
| |
Language |
|
Wos |
000274180600122 |
Publication Date |
2010-01-28 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
0021-8979; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
2.068 |
Times cited |
150 |
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 2.068; 2010 IF: 2.079 |
| |
Call Number |
UA @ lucian @ c:irua:89507 |
Serial |
2146 |
| Permanent link to this record |
| |
|
| |
|
Author |
Nourbakhsh, A.; Cantoro, M.; Klekachev, A.; Clemente, F.; Sorée, B.; van der Veen, M.H.; Vosch, T.; Stesmans, A.; Sels, B.; de Gendt, S. |
| |
Title |
Tuning the Fermi level of SiO2-supported single-layer graphene by thermal annealing |
Type |
A1 Journal article |
| |
Year |
2010 |
Publication |
Journal Of Physical Chemistry C |
Abbreviated Journal |
J Phys Chem C |
| |
Volume |
114 |
Issue |
5 |
Pages |
6894-6900 |
| |
Keywords |
A1 Journal article; Electron Microscopy for Materials Science (EMAT); |
| |
Abstract |
The effects of thermal annealing in inert Ar gas atmosphere of SiO2-supported, exfoliated single-layer graphene are investigated in this work. A systematic, reproducible change in the electronic properties of graphene is observed after annealing. The most prominent Raman features in graphene, the G and 2D peaks, change in accord to what is expected in the case of hole doping. The results of electrical characterization performed on annealed, back-gated field-effect graphene devices show that the neutrality point voltage VNP increases monotonically with the annealing temperature, confirming the occurrence of excess hole accumulation. No degradation of the structural properties of graphene is observed after annealing at temperatures as high as 400 °C. Thermal annealing of single-layer graphene in controlled Ar atmosphere can therefore be considered a technique to reproducibly modify the electronic structure of graphene by tuning its Fermi level. |
| |
Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
| |
Language |
|
Wos |
000276562500002 |
Publication Date |
2010-03-26 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
4.536 |
Times cited |
54 |
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 4.536; 2010 IF: 4.524 |
| |
Call Number |
UA @ lucian @ c:irua:89508 |
Serial |
3757 |
| Permanent link to this record |
| |
|
| |
|
Author |
O'Regan, T.P.; Hurley, P.K.; Sorée, B.; Fischetti, M.V. |
| |
Title |
Modeling the capacitance-voltage response of In0.53Ga0.47As metal-oxide-semiconductor structures : charge quantization and nonparabolic corrections |
Type |
A1 Journal article |
| |
Year |
2010 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl Phys Lett |
| |
Volume |
96 |
Issue |
21 |
Pages |
213514,1-213514,3 |
| |
Keywords |
A1 Journal article; Electron Microscopy for Materials Science (EMAT); |
| |
Abstract |
The capacitance-voltage (C-V) characteristic is calculated for p-type In<sub>0.53</sub>Ga<sub>0.47</sub>As metal-oxide-semiconductor (MOS) structures based on a self-consistent PoissonSchrödinger solution. For strong inversion, charge quantization leads to occupation of the satellite valleys which appears as a sharp increase in the capacitance toward the oxide capacitance. The results indicate that the charge quantization, even in the absence of interface defects (D<sub>it</sub>), is a contributing factor to the experimental observation of an almost symmetric C-V response for In<sub>0.53</sub>Ga<sub>0.47</sub>As MOS structures. In addition, nonparabolic corrections are shown to enhance the depopulation of the Γ valley, shifting the capacitance increase to lower inversion charge densities. |
| |
Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
| |
Language |
|
Wos |
000278183200090 |
Publication Date |
2010-05-28 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
3.411 |
Times cited |
26 |
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: 3.411; 2010 IF: 3.841 |
| |
Call Number |
UA @ lucian @ c:irua:89509 |
Serial |
2143 |
| Permanent link to this record |
| |
|
| |
|
Author |
Sorée, B.; Magnus, W.; Szepieniec, M.; Vandenbreghe, W.; Verhulst, A.; Pourtois, G.; Groeseneken, G.; de Gendt, S.; Heyns, M. |
| |
Title |
Novel device concepts for nanotechnology : the nanowire pinch-off FET and graphene tunnelFET |
Type |
A2 Journal article |
| |
Year |
2010 |
Publication |
ECS transactions |
Abbreviated Journal |
|
| |
Volume |
28 |
Issue |
|
Pages |
15-26 |
| |
Keywords |
A2 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| |
Abstract |
We explain the basic operation of a nanowire pinch-off FET and graphene nanoribbon tunnelFET. For the nanowire pinch-off FET we construct an analytical model to obtain the threshold voltage as a function of radius and doping density. We use the gradual channel approximation to calculate the current-voltage characteristics of this device and we show that the nanowire pinch-off FET has a subthreshold slope of 60 mV/dec and good ION and ION/IOFF ratios. For the graphene nanoribbon tunnelFET we show that an improved analytical model yields more realistic results for the transmission probability and hence the tunneling current. The first simulation results for the graphene nanoribbon tunnelFET show promising subthreshold slopes. |
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Address |
|
| |
Corporate Author |
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Thesis |
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
| |
Language |
|
Wos |
|
Publication Date |
0000-00-00 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1938-5862 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
| |
Notes |
|
Approved |
Most recent IF: NA |
| |
Call Number |
UA @ lucian @ c:irua:89510 |
Serial |
2375 |
| Permanent link to this record |
| |
|
| |
|
Author |
Jehanathan, N.; Georgieva, V.; Saraiva, M.; Depla, D.; Bogaerts, A.; Van Tendeloo, G. |
| |
Title |
The influence of Cr and Y on the micro structural evolution of Mg―Cr―O and Mg―Y―O thin films |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
Thin solid films : an international journal on the science and technology of thin and thick films |
Abbreviated Journal |
Thin Solid Films |
| |
Volume |
519 |
Issue |
16 |
Pages |
5388-5396 |
| |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Electron microscopy for materials research (EMAT) |
| |
Abstract |
The compositional influence of Cr and Y on the microstructure of Mg―Cr―O, and Mg―Y―O films synthesized by reactive magnetron sputtering has been investigated by transmission electron microscopy, X-ray diffraction and molecular dynamics simulations. A decrease in crystallinity is observed in these films as the M (Cr or Y) content is increased. It is found that M forms a solid solution with MgO for metal ratios up to ~ 70% and ~ 50% for Cr and Y respectively. Above ~ 70% Cr metal ratio the Mg―Cr―O films are found to be completely amorphous. The Mg―Y―O films are composed of Mg(Y)O and Y2O3 nano crystallites, up to ~ 50% Y metal ratio. Above this ratio, only Y2O3 nano crystallites are found. The preferential < 111> MgO grain alignment is strongly affected by the increase in M content. For M metal ratios up to ~ 50%, there is a selective promotion of the < 100> MgO grain alignments and a decline in the < 111> grain alignments. |
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Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
Lausanne |
Editor |
|
| |
Language |
|
Wos |
000292573500013 |
Publication Date |
2011-02-26 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
0040-6090; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
1.879 |
Times cited |
4 |
Open Access |
|
| |
Notes |
Iwt |
Approved |
Most recent IF: 1.879; 2011 IF: 1.890 |
| |
Call Number |
UA @ lucian @ c:irua:89516 |
Serial |
1618 |
| Permanent link to this record |
| |
|
| |
|
Author |
Dixit, H.; Tandon, N.; Cottenier, S.; Saniz, R.; Lamoen, D.; Partoens, B.; van Speybroeck, V.; Waroquier, M. |
| |
Title |
Electronic structure and band gap of zinc spinel oxides beyond LDA : ZnAl2O4, ZnGa2O4 and ZnIn2O4 |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
New journal of physics |
Abbreviated Journal |
New J Phys |
| |
Volume |
13 |
Issue |
6 |
Pages |
063002-063002,11 |
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
| |
Abstract |
We examine the electronic structure of the family of ternary zinc spinel oxides ZnX2O4 (X=Al, Ga and In). The band gap of ZnAl2O4 calculated using density functional theory (DFT) is 4.25 eV and is overestimated compared with the experimental value of 3.83.9 eV. The DFT band gap of ZnGa2O4 is 2.82 eV and is underestimated compared with the experimental value of 4.45.0 eV. Since DFT typically underestimates the band gap in the oxide system, the experimental measurements for ZnAl2O4 probably require a correction. We use two first-principles techniques capable of describing accurately the excited states of semiconductors, namely the GW approximation and the modified BeckeJohnson (MBJ) potential approximation, to calculate the band gap of ZnX2O4. The GW and MBJ band gaps are in good agreement with each other. In the case of ZnAl2O4, the predicted band gap values are >6 eV, i.e. ~2 eV larger than the only reported experimental value. We expect future experimental work to confirm our results. Our calculations of the electron effective masses and the second band gap indicate that these compounds are very good candidates to act as transparent conducting host materials. |
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Address |
|
| |
Corporate Author |
|
Thesis |
|
| |
Publisher |
|
Place of Publication |
Bristol |
Editor |
|
| |
Language |
|
Wos |
000292137500002 |
Publication Date |
2011-06-03 |
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
| |
ISSN |
1367-2630; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| |
Impact Factor |
3.786 |
Times cited |
98 |
Open Access |
|
| |
Notes |
Iwt; Fwo; Bof-Noi |
Approved |
Most recent IF: 3.786; 2011 IF: 4.177 |
| |
Call Number |
UA @ lucian @ c:irua:89555 |
Serial |
1008 |
| Permanent link to this record |
| |
|
| |
|
Author |
Shenderova, O.; Koscheev, A.; Zaripov, N.; Petrov, I.; Skryabin, Y.; Detkov, P.; Turner, S.; Van Tendeloo, G. |
| |
Title |
Surface chemistry and properties of ozone-purified detonation nanodiamonds |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
| |
Volume |
115 |
Issue |
20 |
Pages |
9827-9837 |
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| |
Abstract |
Nanodiamond from ozone purification (NDO) demonstrates very distinctive properties within the class of detonation nanodiamonds, namely very high acidity and high colloidal stability in a broad pH range. To understand the origin of these unusual properties of NDO, the nature of the surface functional groups formed during detonation soot oxidation by ozone needs to be revealed. In this work, thermal desorption mass spectrometry (TDMS) and IR spectroscopy were used for the identification of surface groups and it was concluded that carboxylic anhydride groups prevail on the NDO surface. On the basis of the temperature profiles of the desorbed volatile products and their mass balance, it is hypothesized that decomposition of carboxylic anhydride groups from NDO during heating proceeds by two different mechanisms. Other distinctive features of NDO in comparison with air-treated nanodiamond are also reported. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000290652200001 |
Publication Date |
2011-04-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
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ISSN |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
105 |
Open Access |
|
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Notes |
Esteem 026019; Fwo |
Approved |
Most recent IF: 4.536; 2011 IF: 4.805 |
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Call Number |
UA @ lucian @ c:irua:89556 |
Serial |
3394 |
| Permanent link to this record |
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Author |
Boschker, H.; Huijben, M.; Vailinois, A.; Verbeeck, J.; Van Aert, S.; Luysberg, M.; Bals, S.; Van Tendeloo, G.; Houwman, E.P.; Koster, G.; Blank, D.H.A.; Rijnders, G. |
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Title |
Optimized fabrication of high-quality La0.67Sr0.33MnO3 thin films considering all essential characteristics |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of physics: D: applied physics |
Abbreviated Journal |
J Phys D Appl Phys |
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Volume |
44 |
Issue |
20 |
Pages |
205001-205001,9 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
In this paper, an overview of the fabrication and properties of high-quality La0.67Sr0.33MnO3 (LSMO) thin films is given. A high-quality LSMO film combines a smooth surface morphology with a large magnetization and a small residual resistivity, while avoiding precipitates and surface segregation. In the literature, typically only a few of these issues are adressed. We therefore present a thorough characterization of our films, which were grown by pulsed laser deposition. The films were characterized with reflection high energy electron diffraction, atomic force microscopy, x-ray diffraction, magnetization and transport measurements, x-ray photoelectron spectroscopy and scanning transmission electron microscopy. The films have a saturation magnetization of 4.0 µB/Mn, a Curie temperature of 350 K and a residual resistivity of 60 µΩ cm. These results indicate that high-quality films, combining both large magnetization and small residual resistivity, were realized. A comparison between different samples presented in the literature shows that focussing on a single property is insufficient for the optimization of the deposition process. For high-quality films, all properties have to be adressed. For LSMO devices, the thin-film quality is crucial for the device performance. Therefore, this research is important for the application of LSMO in devices. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
London |
Editor |
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Language |
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Wos |
000290150900001 |
Publication Date |
2011-04-29 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-3727;1361-6463; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.588 |
Times cited |
99 |
Open Access |
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Notes |
This research was financially supported by the Dutch Science Foundation, by NanoNed, a nanotechnology program of the Dutch Ministry of Economic Affairs, and by the NanOxide program of the European Science Foundation. This work is supported in part by the Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under contract DE-AC02-76SF00515. |
Approved |
Most recent IF: 2.588; 2011 IF: 2.544 |
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Call Number |
UA @ lucian @ c:irua:89557UA @ admin @ c:irua:89557 |
Serial |
2491 |
| Permanent link to this record |
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Author |
Georgieva, V.; Voter, A.F.; Bogaerts, A. |
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Title |
Understanding the surface diffusion processes during magnetron sputter-deposition of complex oxide Mg-Al-O thin films |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Crystal growth & design |
Abbreviated Journal |
Cryst Growth Des |
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Volume |
11 |
Issue |
6 |
Pages |
2553-2558 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
It is known that film structure may change dramatically with the extent of surface diffusion during the film growth process. In the present work, surface diffusion, induced thermally or activated by energetic impacts, is investigated theoretically under conditions appropriate for magnetron sputter-deposition of MgAlO thin films with varying stoichiometry. The distribution of surface diffusion energy barriers available to the system was determined for each stoichiometry, which allowed assessing in a qualitative way how much surface diffusion will take place on the time scale available between deposition events. The activation energy barriers increase with the Al concentration in the film, and therefore, the surface diffusion rates in the time frame of typical deposition rates drop, which can explain the decrease in crystallinity in the film structure and the transition to amorphous structure. The deposition process and the immediate surface diffusion enhanced by the energetic adatoms are simulated by means of a molecular dynamics model. The longer-time thermal surface diffusion and the energy landscape are studied by the temperature accelerated dynamics method, applied in an approximate way. The surface diffusion enhanced by the energetic impacts appears to be very important for the film structure in the low-temperature deposition regime. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000291074600068 |
Publication Date |
2011-04-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
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ISSN |
1528-7483;1528-7505; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.055 |
Times cited |
14 |
Open Access |
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Notes |
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Approved |
Most recent IF: 4.055; 2011 IF: 4.720 |
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Call Number |
UA @ lucian @ c:irua:89566 |
Serial |
3806 |
| Permanent link to this record |
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Author |
Krüger, P.; da Pieve, F.; Osterwalder, J. |
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Title |
Real-space multiple scattering method for angle-resolved photoemission and valence-band photoelectron diffraction and its application to Cu(111) |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
83 |
Issue |
11 |
Pages |
115437,1-115437,8 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
A computational method is presented for angle-resolved photoemission spectra (ARPES) and photoelectron diffraction (PED) in the ultraviolet regime. The one-step model is employed and both initial valence and final continuum states are calculated using the finite-cluster, real-space multiple scattering method. Thereby the approach is versatile and provides a natural link to core-level PED. The method is applied to the Cu(111) valence band and good agreement with experiment is found for both ARPES spectra and PED patterns. When the PED patterns are integrated over a filled band of a single-orbital symmetry, such as Cu-3d, we show, both numerically and analytically, that the exact theory with delocalized initial states can be replaced by the much simpler, core-level-type theory where the initial states are taken as localized. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000288594500005 |
Publication Date |
2011-03-22 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
17 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:89599 |
Serial |
2831 |
| Permanent link to this record |
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Author |
Michel, K.H.; Verberck, B. |
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Title |
Phonon dispersions and piezoelectricity in bulk and multilayers of hexagonal boron nitride |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
83 |
Issue |
11 |
Pages |
115328-115328,14 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
A unified theory of phonon dispersions and piezoelectricity in bulk and multilayers of hexagonal boron nitride (h-BN) is derived. The dynamical matrix is calculated on the basis of an empirical force constant model of intralayer valence and interlayer van der Waals interactions. Coulomb interactions are calculated by Ewalds method, adapted for the three-dimensional (3D) and the multilayer case. The deformation of the ionic charge distribution with long-wave lattice displacements is taken into account. Special attention is devoted to the nonanalytic long-range Coulomb contribution to the dynamical matrix which is different for the 3D crystal and the multilayer case. Consequently there is a splitting of the transverse optical (TO) and longitudinal optical (LO) phonon branches of E1u symmetry and a discontinuity of the A2u branch at the Γ point in 3D h-BN. No such splitting and discontinuity at Γ are present in multilayer crystals with a finite number N of layers. There a diverging bundle of N overbending optical phonon branches emerges from Γ. Borns long-wave theory is applied and extended for the study of piezoelectricity in layered crystals. While 3D h-BN and h-BN multilayers with an even number of layers (symmetry D6h) are not piezoelectric, multilayers with an uneven number of Nu layers (symmetry D3h) are piezoelectric; the piezoelectric coefficient e1,11 is inversely proportional to Nu. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000288783700005 |
Publication Date |
2011-03-24 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
82 |
Open Access |
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Notes |
; Discussions with G. Heger, B. Partoens, and F. M. Peeters are gratefully acknowledged. This work has been supported by the Flemish Science Foundation (FWO-V1) and the Bijzonder Onderzoeksfonds, Universiteit Antwerpen (BOF-UA). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:89602 |
Serial |
2603 |
| Permanent link to this record |
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Author |
Sullivan, E.; Hadermann, J.; Greaves, C. |
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Title |
Crystallographic and magnetic characterisation of the brownmillerite Sr2Co2O5 |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of solid state chemistry |
Abbreviated Journal |
J Solid State Chem |
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Volume |
184 |
Issue |
3 |
Pages |
649-654 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Sr2Co2O5 with the perovskite-related brownmillerite structure has been synthesised via quenching, with the orthorhombic unit cell parameters a=5.4639(3) Å, b=15.6486(8) Å and c=5.5667(3) Å based on refinement of neutron powder diffraction data collected at 4 K. Electron microscopy revealed LRLR-intralayer ordering of chain orientations, which require a doubling of the unit cell along the c-parameter, consistent with the assignment of the space group Pcmb. However, on the length scale pertinent to NPD, no long-range order is observed and the disordered space group Imma appears more appropriate. The magnetic structure corresponds to G-type order with a moment of 3.00(4) μB directed along [1 0 0]. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
London |
Editor |
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Language |
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Wos |
000288587800026 |
Publication Date |
2011-01-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-4596; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.299 |
Times cited |
19 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.299; 2011 IF: 2.159 |
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Call Number |
UA @ lucian @ c:irua:89650 |
Serial |
584 |
| Permanent link to this record |
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Author |
van den Broek, W.; Van Aert, S.; Goos, P.; van Dyck, D. |
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Title |
Throughput maximization of particle radius measurements by balancing size and current of the electron probe |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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Volume |
111 |
Issue |
7 |
Pages |
940-947 |
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Keywords |
A1 Journal article; Engineering Management (ENM); Electron microscopy for materials research (EMAT); Vision lab |
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Abstract |
In thispaperweinvestigatewhichprobesizemaximizesthethroughputwhenmeasuringtheradiusof nanoparticlesinhighangleannulardarkfieldscanningtransmissionelectronmicroscopy(HAADFSTEM). The sizeandthecorrespondingcurrentoftheelectronprobedeterminetheprecisionoftheestimateofa particlesradius.Maximizingthroughputmeansthatamaximumnumberofparticlesshouldbeimaged withinagiventimeframe,sothataprespecifiedprecisionisattained.WeshowthatBayesianstatistical experimentaldesignisaveryusefulapproachtodeterminetheoptimalprobesizeusingacertainamount of priorknowledgeaboutthesample.Thedependenceoftheoptimalprobesizeonthedetectorgeometry and thediameter,variabilityandatomicnumberoftheparticlesisinvestigated.Anexpressionforthe optimalprobesizeintheabsenceofanykindofpriorknowledgeaboutthespecimenisderivedaswell. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000300461000026 |
Publication Date |
2010-11-25 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0304-3991; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.843 |
Times cited |
7 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.843; 2011 IF: 2.471 |
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Call Number |
UA @ lucian @ c:irua:89657 |
Serial |
3659 |
| Permanent link to this record |
