NANOlab Center of Excellence literature database -- Query Results

	NANOlab Center of Excellence literature database Home \| Show All \| Simple Search \| Advanced Search	Login Quick Search: Field: contains: ...
	151–180 of 332 records found matching your query (RSS):

Select All Deselect All

<< 1 2 3 4 5 6 7 8 9 10 11 12 >>

List View

Citations

Details

	Records
	Author	Aerts, A.; Follens, L.R.A.; Biermans, E.; Bals, S.; Van Tendeloo, G.; Loppinet, B.; Kirschhock, C.E.A.; Martens, J.A.
	Title	Modelling of synchrotron SAXS patterns of silicalite-1 zeolite during crystallization			Type	A1 Journal article
	Year	2011	Publication	Physical chemistry, chemical physics	Abbreviated Journal	Phys Chem Chem Phys
	Volume	13	Issue	10	Pages	4318-4325
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Synchrotron small angle X-ray scattering (SAXS) was used to characterize silicalite-1 zeolite crystallization from TEOS/TPAOH/water clear sol. SAXS patterns were recorded over a broad range of length scales, enabling the simultaneous monitoring of nanoparticles and crystals occurring at various stages of the synthesis. A simple two-population model accurately described the patterns. Nanoparticles were modeled by polydisperse coreshell spheres and crystals by monodisperse oblate ellipsoids. These models were consistent with TEM images. The SAXS results, in conjunction with in situ light scattering, showed that nucleation of crystals occurred in a short period of time. Crystals were uniform in size and shape and became increasingly anisotropic during growth. In the presence of nanoparticles, crystal growth was fast. During crystal growth, the number of nanoparticles decreased gradually but their size was constant. These observations suggested that the nanoparticles were growth units in an aggregative crystal growth mechanism. Crystals grown in the presence of nanoparticles developed a faceted habit and intergrowths. In the final stages of growth, nanoparticles were depleted. Concurrently, the crystal growth rate decreased significantly.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Cambridge	Editor
	Language		Wos	000287584700017	Publication Date	2011-01-24
	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	22	Open Access
	Notes	Fwo; Iap; Esteem 026019			Approved	Most recent IF: 4.123; 2011 IF: 3.573
	Call Number	UA @ lucian @ c:irua:87602			Serial	2155
Permanent link to this record



	Author	Talgorn, E.; Gao, Y.; Aerts, M.; Kunneman, L.T.; Schins, J.M.; Savenije, T.J.; van Huis, M.A.; van der Zant, H.S.J.; Houtepen, A.J.; Siebbeles, L.D.A.
	Title	Unity quantum yield of photogenerated charges and band-like transport in quantum-dot solids			Type	A1 Journal article
	Year	2011	Publication	Nature nanotechnology	Abbreviated Journal	Nat Nanotechnol
	Volume	6	Issue	11	Pages	733-739
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Solid films of colloidal quantum dots show promise in the manufacture of photodetectors and solar cells. These devices require high yields of photogenerated charges and high carrier mobilities, which are difficult to achieve in quantum-dot films owing to a strong electronhole interaction and quantum confinement. Here, we show that the quantum yield of photogenerated charges in strongly coupled PbSe quantum-dot films is unity over a large temperature range. At high photoexcitation density, a transition takes place from hopping between localized states to band-like transport. These strongly coupled quantum-dot films have electrical properties that approach those of crystalline bulk semiconductors, while retaining the size tunability and cheap processing properties of colloidal quantum dots.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000296737300012	Publication Date	2011-09-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1748-3387;1748-3395;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	38.986	Times cited	129	Open Access
	Notes				Approved	Most recent IF: 38.986; 2011 IF: 27.270
	Call Number	UA @ lucian @ c:irua:93296			Serial	3813
Permanent link to this record



	Author	Van Aert, S.; Batenburg, K.J.; Rossell, M.D.; Erni, R.; Van Tendeloo, G.
	Title	Three-dimensional atomic imaging of crystalline nanoparticles			Type	A1 Journal article
	Year	2011	Publication	Nature	Abbreviated Journal	Nature
	Volume	470	Issue	7334	Pages	374-377
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
	Abstract	Determining the three-dimensional (3D) arrangement of atoms in crystalline nanoparticles is important for nanometre-scale device engineering and also for applications involving nanoparticles, such as optoelectronics or catalysis. A nanoparticles physical and chemical properties are controlled by its exact 3D morphology, structure and composition1. Electron tomography enables the recovery of the shape of a nanoparticle from a series of projection images2, 3, 4. Although atomic-resolution electron microscopy has been feasible for nearly four decades, neither electron tomography nor any other experimental technique has yet demonstrated atomic resolution in three dimensions. Here we report the 3D reconstruction of a complex crystalline nanoparticle at atomic resolution. To achieve this, we combined aberration-corrected scanning transmission electron microscopy5, 6, 7, statistical parameter estimation theory8, 9 and discrete tomography10, 11. Unlike conventional electron tomography, only two images of the targeta silver nanoparticle embedded in an aluminium matrixare sufficient for the reconstruction when combined with available knowledge about the particles crystallographic structure. Additional projections confirm the reliability of the result. The results we present help close the gap between the atomic resolution achievable in two-dimensional electron micrographs and the coarser resolution that has hitherto been obtained by conventional electron tomography.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	London	Editor
	Language		Wos	000287409100037	Publication Date	2011-02-02
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0028-0836;1476-4687;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	40.137	Times cited	341	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 40.137; 2011 IF: 36.280
	Call Number	UA @ lucian @ c:irua:86745			Serial	3644
Permanent link to this record



	Author	Tognalii, N.G.; Cortés, E.; Hernández-Nieves, A.D.; Carro, P.; Usaj, G.; Balseiro, C.A.; Vela, M.E.; Salvarezza, R.C.; Fainstein, A.
	Title	From single to multiple Ag-layer modification of Au nanocavity substrates : a tunable probe of the chemical surface-enhanced Raman scattering mechanism			Type	A1 Journal article
	Year	2011	Publication	ACS nano	Abbreviated Journal	Acs Nano
	Volume	5	Issue	7	Pages	5433-5443
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We present experimental and computational results that enlighten the mechanisms underlying the chemical contribution to surface-enhanced Raman scattering (SERS). Gold void metallic arrays electrochemically covered either by a Ag monolayer or 10100 Ag layers were modified with a self-assembled monolayer of 4-mercaptopyridine as a molecular Raman probe displaying a rich and unexpected Raman response. A resonant increase of the Raman intensity in the red part of the spectrum is observed that cannot be related to plasmon excitations of the cavity-array. Notably, we find an additional 1020 time increase of the SERS amplification upon deposition of a single Ag layer on the Au substrate, which is, however, almost quenched upon deposition of 10 atomic layers. Further deposition of 100 atomic Ag layers results in a new increase of the SERS signal, consistent with the improved plasmonic efficiency of Ag bulk-like structures. The SERS response as a function of the Ag layer thickness is analyzed in terms of ab initio calculations and a microscopic model for the SERS chemical mechanism based on a resonant charge transfer process between the molecular HOMO state and the Fermi level in the metal surface. We find that a rearrangement of the electronic charge density related to the presence of the Ag monolayer in the Au/Ag/molecule complex causes an increase in the distance between the HOMO center of charge and the metallic image plane that is responsible for the variation of Raman enhancement between the studied substrates. Our results provide a general platform for studying the chemical contribution to SERS, and for enhancing the Raman efficiency of tailored Au-SERS templates through electrochemical modification with Ag films.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000293035200019	Publication Date	2011-06-15
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1936-0851;1936-086X;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	13.942	Times cited	26	Open Access
	Notes	; We acknowledge financial support from ANPCyT (Argentina, PICT08-1617, PICT08-2236, PICT06-621, PICT-CNPQ-08-0019, PAE 22711, PICT06-01061, PICT06-483) and Project CTQ2008-06017/BQU, Spain. N.G.T, E.C., A.D.H.N., R.C.S, G.U., C.A.B., and A.F. are also at CONICET. M.E.V. is a member of the research career of CIC BsAs. R.C.S., C.A.B., and A.F. are Guggenheim Foundation Fellows. We would like to thank Dr. M. H. Fonticelli for fruitful discussions on the electrochemical measurements and Dr. H. Pastoriza for the help with the SEM measurements. ;			Approved	Most recent IF: 13.942; 2011 IF: 11.421
	Call Number	UA @ lucian @ c:irua:91775			Serial	1285
Permanent link to this record



	Author	van Huis, M.A.; Figuerola, A.; Fang, C.; Béché, A.; Zandbergen, H.W.; Manna, L.
	Title	Letter Chemical transformation of Au-tipped CdS nanorods into AuS/Cd core/shell particles by electron beam irradiation			Type	A1 Journal article
	Year	2011	Publication	Nano letters	Abbreviated Journal	Nano Lett
	Volume	11	Issue	11	Pages	4555-4561
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	We demonstrate that electron irradiation of colloidal CdS nanorods carrying Au domains causes their evolution into AuS/Cd core/shell nanoparticles as a result of a concurrent chemical and morphological transformation. The shrinkage of the CdS nanorods and the growth of the Cd shell around the Au tips are imaged in real time, while the displacement of S atoms from the CdS nanorod to the Au domains is evidenced by high-sensitivity energy-dispersive X-ray (EDX) spectroscopy. The various nanodomains display different susceptibility to the irradiation, which results in nanoconfigurations that are very different from those obtained after thermal annealing. Such physical manipulations of colloidal nanocrystals can be exploited as a tool to access novel nanocrystal heterostructures.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington	Editor
	Language		Wos	000296674700009	Publication Date	2011-10-13
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1530-6984;1530-6992;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	12.712	Times cited	25	Open Access
	Notes				Approved	Most recent IF: 12.712; 2011 IF: 13.198
	Call Number	UA @ lucian @ c:irua:93710			Serial	1814
Permanent link to this record



	Author	Cooper, D.; de la Peña, F.; Béché, A.; Rouvière, J.-L.; Servanton, G.; Pantel, R.; Morin, P.
	Title	Field mapping with nanometer-scale resolution for the next generation of electronic devices			Type	A1 Journal article
	Year	2011	Publication	Nano letters	Abbreviated Journal	Nano Lett
	Volume	11	Issue	11	Pages	4585-4590
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	In order to improve the performance of todays nanoscaled semiconductor devices, characterization techniques that can provide information about the position and activity of dopant atoms and the strain fields are essential. Here we demonstrate that by using a modern transmission electron microscope it is possible to apply multiple techniques to advanced materials systems in order to provide information about the structure, fields, and composition with nanometer-scale resolution. Off-axis electron holography has been used to map the active dopant potentials in state-of-the-art semiconductor devices with 1 nm resolution. These dopant maps have been compared to electron energy loss spectroscopy maps that show the positions of the dopant atoms. The strain fields in the devices have been measured by both dark field electron holography and nanobeam electron diffraction.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington	Editor
	Language		Wos	000296674700014	Publication Date	2011-10-05
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1530-6984	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	12.712	Times cited	12	Open Access
	Notes				Approved	Most recent IF: 12.712; 2011 IF: 13.198
	Call Number	UA @ lucian @ c:irua:136369			Serial	4499
Permanent link to this record



	Author	Barreca, D.; Carraro, G.; Gasparotto, A.; Maccato, C.; Lebedev, O.I.; Parfenova, A.; Turner, S.; Tondello, E.; Van Tendeloo, G.
	Title	Tailored vapor-phase growth of Cu_xO-TiO₂(x=1,2) nanomaterials decorated with Au particles			Type	A1 Journal article
	Year	2011	Publication	Langmuir: the ACS journal of surfaces and colloids	Abbreviated Journal	Langmuir
	Volume	27	Issue	10	Pages	6409-6417
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	We report on the fabrication of CuxOTiO2 (x = 1, 2) nanomaterials by an unprecedented vapor-phase approach. The adopted strategy involves the growth of porous CuxO matrices by means of chemical vapor deposition (CVD), followed by the controlled dispersion of TiO2 nanoparticles. The syntheses are performed on Si(100) substrates at temperatures of 400550 °C under wet oxygen atmospheres, adopting Cu(hfa)2·TMEDA (hfa =1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N′,N′-tetramethylethylenediamine) and Ti(O-iPr)2(dpm)2 (O-iPr = isopropoxy; dpm = 2,2,6,6-tetramethyl-3,5-heptanedionate) as copper and titanium precursors, respectively. Subsequently, finely dispersed gold nanoparticles are introduced in the as-prepared systems via radio frequency (RF)-sputtering under mild conditions. The synthesis process results in the formation of systems with chemical composition and nano-organization strongly dependent on the nature of the initial CuxO matrix and on the deposited TiO2 amount. The decoration with low-size gold clusters paves the way to the engineering of hierarchically organized nanomaterials.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000290292900082	Publication Date	2011-04-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0743-7463;1520-5827;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.833	Times cited	36	Open Access
	Notes	Fwo			Approved	Most recent IF: 3.833; 2011 IF: 4.186
	Call Number	UA @ lucian @ c:irua:88940			Serial	3467
Permanent link to this record



	Author	Vernimmen, J.; Guidotti, M.; Silvestre-Albero, J.; Jardim, E.O.; Mertens, M.; Lebedev, O.I.; Van Tendeloo, G.; Psaro, R.; Rodríguez-Reinoso, F.; Meynen, V.; Cool, P.
	Title	Immersion calorimetry as a tool to evaluate the catalytic performance of titanosilicate materials in the epoxidation of cyclohexene			Type	A1 Journal article
	Year	2011	Publication	Langmuir: the ACS journal of surfaces and colloids	Abbreviated Journal	Langmuir
	Volume	27	Issue	7	Pages	3618-3625
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
	Abstract	Different types of titanosilicates are synthesized, structurally characterized, and subsequently catalytically tested in the liquid-phase epoxidation of cyclohexene. The performance of three types of combined zeolitic/mesoporous materials is compared with that of widely studied Ti-grafted-MCM-41 molecular sieve and the TS-1 microporous titanosilicate. The catalytic test results are correlated with the structural characteristics of the different catalysts. Moreover, for the first time, immersion calorimetry with the same substrate molecule as in the catalytic test reaction is applied as an extra means to interpret the catalytic results. A good correlation between catalytic performance and immersion calorimetry results is found. This work points out that the combination of catalytic testing and immersion calorimetry can lead to important insights into the influence of the materials structural characteristics on catalysis. Moreover, the potential of using immersion calorimetry as a screening tool for catalysts in epoxidation reactions is shown.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000288970900054	Publication Date	2011-02-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0743-7463;1520-5827;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.833	Times cited	19	Open Access
	Notes				Approved	Most recent IF: 3.833; 2011 IF: 4.186
	Call Number	UA @ lucian @ c:irua:88366			Serial	1557
Permanent link to this record



	Author	Khalilov, U.; Neyts, E.C.; Pourtois, G.; van Duin, A.C.T.
	Title	Can we control the thickness of ultrathin silica layers by hyperthermal silicon oxidation at room temperature?			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	50	Pages	24839-24848
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Using reactive molecular dynamics simulations by means of the ReaxFF potential, we studied the growth mechanism of ultrathin silica (SiO2) layers during hyperthermal oxidation at room temperature. Oxidation of Si(100){2 × 1} surfaces by both atomic and molecular oxygen was investigated in the energy range 15 eV. The oxidation mechanism, which differs from thermal oxidation, is discussed. In the case of oxidation by molecular O2, silica is quickly formed and the thickness of the formed layers remains limited compared to oxidation by atomic oxygen. The Si/SiO2 interfaces are analyzed in terms of partial charges and angle distributions. The obtained structures of the ultrathin SiO2 films are amorphous, including some intrinsic defects. This study is important for the fabrication of silica-based devices in the micro- and nanoelectronics industry, and more specifically for the fabrication of metal oxide semiconductor devices.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000297947700050	Publication Date	2011-11-16
	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	36	Open Access
	Notes				Approved	Most recent IF: 4.536; 2011 IF: 4.805
	Call Number	UA @ lucian @ c:irua:94303			Serial	273
Permanent link to this record



	Author	Delabie, A.; Sioncke, S.; Rip, J.; van Elshocht, S.; Caymax, M.; Pourtois, G.; Pierloot, K.
	Title	Mechanisms for the trimethylaluminum reaction in aluminum oxide atomic layer deposition on sulfur passivated germanium			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	35	Pages	17523-17532
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Germanium combined with high-κ dielectrics is investigated for the next generations of CMOS devices. Therefore, we study reaction mechanisms for Al2O3 atomic layer deposition on sulfur passivated Ge using calculations based on density functional theory and total reflection X-ray fluorescence (TXRF). TXRF indicates 6 S/nm2 and 4 Al/nm2 after the first TMA/H2O reaction cycle, and growth inhibition from the second reaction cycle on. Calculations are performed on molecular clusters representing −GeSH surface sites. The calculations confirm that the TMA reaction does not affect the S content. On fully SH-terminated Ge, TMA favorably reacts with up to three −GeSH sites, resulting in a near tetrahedral Al coordination. Electron deficient structures with a GeS site shared between two Al atoms are proposed. The impact of the cluster size on the structures and reaction energetics is systematically investigated.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000294386000037	Publication Date	2011-08-01
	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	9	Open Access
	Notes				Approved	Most recent IF: 4.536; 2011 IF: 4.805
	Call Number	UA @ lucian @ c:irua:91714			Serial	1980
Permanent link to this record



	Author	Bittencourt, C.; Navio, C.; Nicolay, A.; Ruelle, B.; Godfroid, T.; Snyders, R.; Colomer, J.-F.; Lagos, M.J.; Ke, X.; Van Tendeloo, G.; Suarez-Martinez, I.; Ewels, C.P.
	Title	Atomic oxygen functionalization of vertically aligned carbon nanotubes			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	42	Pages	20412-20418
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Vertically aligned multiwalled carbon nanotubes (v-MWCNTs) are functionalized using atomic oxygen generated in a microwave plasma. X-ray photoelectron spectroscopy depth profile analysis shows that the plasma treatment effectively grafts oxygen exclusively at the v-MWCNT tips. Electron microscopy shows that neither the vertical alignment nor the structure of v-MWCNTs were affected by the plasma treatment. Density functional calculations suggest assignment of XPS C 1s peaks at 286.6 and 287.5 eV, to epoxy and carbonyl functional groups, respectively.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000296205600009	Publication Date	2011-10-04
	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	31	Open Access
	Notes	Iap			Approved	Most recent IF: 4.536; 2011 IF: 4.805
	Call Number	UA @ lucian @ c:irua:91890			Serial	174
Permanent link to this record



	Author	Nourbakhsh, A.; Cantoro, M.; Klekachev, A.V.; Pourtois, G.; Vosch, T.; Hofkens, J.; van der Veen, M.H.; Heyns, M.M.; de Gendt, S.; Sels, B.F.
	Title	Single layer vs bilayer graphene : a comparative study of the effects of oxygen plasma treatment on their electronic and optical properties			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	33	Pages	16619-16624
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	This contribution presents the effects of a mild O2 plasma treatment on the structural, optical, and electrical properties of single-layer (SLG) and bilayer graphene (BLG). Unexpectedly, we observe only photoluminescence in the SLG parts of a graphene flake composed of regions of various thickness upon O2 plasma treatment, whereas the BLG and few-layer graphene (FLG) parts remain optically unchanged. Confirmed with X-ray photoelectron spectroscopy (XPS) that O2 plasma induces epoxide and hydroxyl-like groups in graphene, density functional theory (DFT) calculations are carried out on representative epoxidized and hydroxylated SLG and BLG models to predict density of states (DOS) and band structures. Sufficiently oxidized SLG shows a bandgap and thus loss of semimetallic behavior, while oxidized BLG maintains its semimetallic behavior even at high oxygen density in agreement with the results of the photoluminescence spectroscopy (PL) experiments. DFT calculations confirm that the Fermi velocity in epoxidized BLG is remarkably comparable with that of pristine SLG, pointing to a similarity of electronic band structure. The similarity is also experimentally demonstrated by the electrical characterization of a plasma-treated BLG-FET. As expected from the electronegative oxygen adatoms in the graphene, epoxidized BLG presents conductive features typical of hole doping. Moreover, the electrical characteristics suggest band structures closely related to that of epoxidized graphene while deviating from that of hydroxylated graphene. Finally, upon O2 plasma treatment of BLG, the four-component 2D peak around 2700 cm1 in the Raman spectrum evolves into a single Lorentzian line, very like the 2D peak of pristine SLG. Summarizing, the data in this contribution recommend that a controlled O2 plasma treatment, which is compatible with CMOS process flow in contrast to wet chemical oxidation methods, provides an efficient and valuable technique to exploit the transport properties of the bottom layer of BLG.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000294077000047	Publication Date	2011-06-24
	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	46	Open Access
	Notes				Approved	Most recent IF: 4.536; 2011 IF: 4.805
	Call Number	UA @ lucian @ c:irua:91715			Serial	3024
Permanent link to this record



	Author	Shenderova, O.A.; Vlasov, I.I.; Turner, S.; Van Tendeloo, G.; Orlinskii, S.B.; Shiryaev, A.A.; Khomich, A.A.; Sulyanov, S.N.; Jelezko, F.; Wrachtrup, J.
	Title	Nitrogen control in nanodiamond produced by detonation shock-wave-assisted synthesis			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	29	Pages	14014-14024
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Development of efficient production methods of nanodiamond (ND) particles containing substitutional nitrogen and nitrogen-vacancy (NV) complexes remains an important goal in the nanodiamond community. ND synthesized from explosives is generally not among the preferred candidates for imaging applications owing to lack of optically active particles containing NV centers. In this paper, we have systematically studied representative classes of NDs produced by detonation shock wave conversion of different carbon precursor materials, namely, graphite and a graphite/hexogen mixture into ND, as well as ND produced from different combinations of explosives using different cooling methods (wet or dry cooling). We demonstrate that (i) the N content in nanodiamond particles can be controlled through a correct selection of the carbon precursor material (addition of graphite, explosives composition); (ii) particles larger than approximately 20 nm may contain in situ produced optically active NV centers, and (iii) in ND produced from explosives, NV centers are detected only in ND produced by wet synthesis. ND synthesized from a mixture of graphite/explosive contains the largest amount of NV centers formed during synthesis and thus deserves special attention.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000292892500009	Publication Date	2011-06-08
	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	Esteem 026019; Fwo			Approved	Most recent IF: 4.536; 2011 IF: 4.805
	Call Number	UA @ lucian @ c:irua:91259			Serial	2342
Permanent link to this record



	Author	Neyts, E.C.; Khalilov, U.; Pourtois, G.; van Duin, A.C.T.
	Title	Hyperthermal oxygen interacting with silicon surfaces : adsorption, implantation, and damage creation			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	15	Pages	4818-4823
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Using reactive molecular dynamics simulations, we have investigated the effect of single-impact, low-energy (thermal-100 eV) bombardment of a Si(100){2 × 1} surface by atomic and molecular oxygen. Penetration probability distributions, as well as defect formation distributions, are presented as a function of the impact energy for both species. It is found that at low impact energy, defects are created chemically due to the chemisorption process in the top layers of the surface, while at high impact energy, additional defects are created by a knock-on displacement of Si. These results are of particular importance for understanding device performances of silica-based microelectronic and photovoltaic devices.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000288401200060	Publication Date	2011-03-02
	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	28	Open Access
	Notes				Approved	Most recent IF: 4.536; 2011 IF: 4.805
	Call Number	UA @ lucian @ c:irua:89858			Serial	1543
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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000290652200001	Publication Date	2011-04-28
	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	105	Open Access
	Notes	Esteem 026019; Fwo			Approved	Most recent IF: 4.536; 2011 IF: 4.805
	Call Number	UA @ lucian @ c:irua:89556			Serial	3394
Permanent link to this record



	Author	Gasparotto, A.; Barreca, D.; Bekermann, D.; Devi, A.; Fischer, R.A.; Fornasiero, P.; Gombac, V.; Lebedev, O.I.; Maccato, C.; Montini, T.; Van Tendeloo, G.; Tondello, E.
	Title	F-doped Co₃O₄ photocatalysts for sustainable H₂ generation from water/ethanol			Type	A1 Journal article
	Year	2011	Publication	Journal of the American Chemical Society	Abbreviated Journal	J Am Chem Soc
	Volume	133	Issue	48	Pages	19362-19365
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	p-Type Co3O4 nanostructured films are synthesized by a plasma-assisted process and tested in the photocatalytic production of H2 from water/ethanol solutions under both near-UV and solar irradiation. It is demonstrated that the introduction of fluorine into p-type Co3O4 results in a remarkable performance improvement with respect to the corresponding undoped oxide, highlighting F-doped Co3O4 films as highly promising systems for hydrogen generation. Notably, the obtained yields were among the best ever reported for similar semiconductor-based photocatalytic processes.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000297606500027	Publication Date	2011-11-04
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0002-7863;1520-5126;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	13.858	Times cited	114	Open Access
	Notes				Approved	Most recent IF: 13.858; 2011 IF: 9.907
	Call Number	UA @ lucian @ c:irua:93628			Serial	1164
Permanent link to this record



	Author	Dixon, E.; Hadermann, J.; Ramos, S.; Goodwin, A.L.; Hayward, M.A.
	Title	Mn(I) in an extended oxide : the synthesis and characterization of La_1-xCa_xMnO_2+\delta (0.6\leq x\leq1)			Type	A1 Journal article
	Year	2011	Publication	Journal of the American Chemical Society	Abbreviated Journal	J Am Chem Soc
	Volume	133	Issue	45	Pages	18397-18405
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Reduction of La1xCaxMnO3 (0.6 ≤ x ≤ 1) perovskite phases with sodium hydride yields materials of composition La1xCaxMnO2+δ. The calcium-rich phases (x = 0.9, 1) adopt (La0.9Ca0.1)0.5Mn0.5O disordered rocksalt structures. However local structure analysis using reverse Monte Carlo refinement of models against pair distribution functions obtained from neutron total scattering data reveals lanthanum-rich La1xCaxMnO2+δ (x = 0.6, 0.67, 0.7) phases adopt disordered structures consisting of an intergrowth of sheets of MnO6 octahedra and sheets of MnO4 tetrahedra. X-ray absorption data confirm the presence of Mn(I) centers in La1xCaxMnO2+δ phases with x < 1. Low-temperature neutron diffraction data reveal La1xCaxMnO2+δ (x = 0.6, 0.67, 0.7) phases become antiferromagnetically ordered at low temperature.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000297381200065	Publication Date	2011-10-14
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0002-7863;1520-5126;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	13.858	Times cited	33	Open Access
	Notes				Approved	Most recent IF: 13.858; 2011 IF: 9.907
	Call Number	UA @ lucian @ c:irua:94030			Serial	2094
Permanent link to this record



	Author	Esken, D.; Turner, S.; Wiktor, C.; Kalidindi, S.B.; Van Tendeloo, G.; Fischer, R.A.
	Title	GaN@ZIF-8 : selective formation of gallium nitride quantum dots inside a zinc methylimidazolate framework			Type	A1 Journal article
	Year	2011	Publication	Journal of the American Chemical Society	Abbreviated Journal	J Am Chem Soc
	Volume	133	Issue	41	Pages	16370-16373
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The microporous zeolitic imidazolate framework [Zn(MeIM)2; ZIF-8; MeIM = imidazolate-2-methyl] was quantitatively loaded with trimethylamine gallane [(CH3)3NGaH3]. The obtained inclusion compound [(CH3)3NGaH3]@ZIF-8 reveals three precursor molecules per host cavity. Treatment with ammonia selectively yields the caged cyclotrigallazane intermediate (H2GaNH2)3@ZIF-8, and further annealing gives GaN@ZIF-8. This new composite material was characterized with FT-IR spectroscopy, solid-state NMR spectroscopy, powder X-ray diffraction, elemental analysis, (scanning) transmission electron microscopy combined with electron energy-loss spectroscopy, photoluminescence (PL) spectroscopy, and N2 sorption measurements. The data give evidence for the presence of GaN nanoparticles (13 nm) embedded in the cavities of ZIF-8, including a blue-shift of the PL emission band caused by the quantum size effect.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000295997500014	Publication Date	2011-09-13
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0002-7863;1520-5126;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	13.858	Times cited	82	Open Access
	Notes	Hercules			Approved	Most recent IF: 13.858; 2011 IF: 9.907
	Call Number	UA @ lucian @ c:irua:93582			Serial	1315
Permanent link to this record



	Author	Neyts, E.C.; van Duin, A.C.T.; Bogaerts, A.
	Title	Changing chirality during single-walled carbon nanotube growth : a reactive molecular dynamics/Monte Carlo study			Type	A1 Journal article
	Year	2011	Publication	Journal of the American Chemical Society	Abbreviated Journal	J Am Chem Soc
	Volume	133	Issue	43	Pages	17225-17231
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	The growth mechanism and chirality formation of a single-walled carbon nanotube (SWNT) on a surface-bound nickel nanocluster are investigated by hybrid reactive molecular dynamics/force-biased Monte Carlo simulations. The validity of the interatomic potential used, the so-called ReaxFF potential, for simulating catalytic SWNT growth is demonstrated. The SWNT growth process was found to be in agreement with previous studies and observed to proceed through a number of distinct steps, viz., the dissolution of carbon in the metallic particle, the surface segregation of carbon with the formation of aggregated carbon clusters on the surface, the formation of graphitic islands that grow into SWNT caps, and finally continued growth of the SWNT. Moreover, it is clearly illustrated in the present study that during the growth process, the carbon network is continuously restructured by a metal-mediated process, thereby healing many topological defects. It is also found that a cap can nucleate and disappear again, which was not observed in previous simulations. Encapsulation of the nanoparticle is observed to be prevented by the carbon network migrating as a whole over the cluster surface. Finally, for the first time, the chirality of the growing SWNT cap is observed to change from (11,0) over (9,3) to (7,7). It is demonstrated that this change in chirality is due to the metal-mediated restructuring process.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000297380900026	Publication Date	2011-10-06
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0002-7863;1520-5126;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	13.858	Times cited	116	Open Access
	Notes				Approved	Most recent IF: 13.858; 2011 IF: 9.907
	Call Number	UA @ lucian @ c:irua:92043			Serial	309
Permanent link to this record



	Author	Navulla, A.; Tsirlin, A.A.; Abakumov, A.M.; Shpanchenko, R.V.; Zhang, H.; Dikarev, E.V.
	Title	Fluorinated heterometallic \beta-diketonates as volatile single-source precursors for the synthesis of low-valent mixed-metal fluorides			Type	A1 Journal article
	Year	2011	Publication	Journal of the American Chemical Society	Abbreviated Journal	J Am Chem Soc
	Volume	133	Issue	4	Pages	692-694
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Hexafluoroacetylacetonates that contain lead and divalent first-row transition metals, PbM(hfac)4 (M = Ni (1), Co (2), Mn (3), Fe (4), and Zn (5)), have been synthesized. Their heterometallic structures are held together by strong Lewis acid−base interactions between metal atoms and diketonate ligands acting in chelating−bridging fashion. Compounds 1−5 are highly volatile and decompose below 350 °C. Fluorinated heterometallic β-diketonates have been used for the first time as volatile single-source precursors for the preparation of mixed-metal fluorides. Complex fluorides of composition Pb2MF6 have been obtained by decomposition of 1−5 in a two-zone furnace under low-pressure nitrogen flow. Lead−transition metal fluorides conform to orthorhombically distorted Aurivillius-type structure with layers of corner-sharing [MF6] octahedra separated by α-PbO-type (Pb2F2) blocks. Pb2NiF6 and Pb2CoF6 were found to exhibit magnetic ordering below 80 and 43 K, respectively. The ordering is antiferromagnetic, with a weak, uncompensated moment due to the canting of spins. The Pb2MF6 fluorides represent a new class of prospective magnetoelectric materials combining transition metals and lone-pair main-group cations.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000287295300015	Publication Date	2010-12-21
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0002-7863;1520-5126;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	13.858	Times cited	28	Open Access
	Notes				Approved	Most recent IF: 13.858; 2011 IF: 9.907
	Call Number	UA @ lucian @ c:irua:88820			Serial	1236
Permanent link to this record



	Author	King, G.; Abakumov, A.M.; Woodward, P.M.; Llobet, A.; Tsirlin, A.A.; Batuk, D.; Antipov, E.V.
	Title	The high-temperature polymorphs of K₃AlF₆			Type	A1 Journal article
	Year	2011	Publication	Inorganic chemistry	Abbreviated Journal	Inorg Chem
	Volume	50	Issue	16	Pages	7792-7801
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The crystal structures of the three high-temperature polymorphs of K3AlF6 have been solved from neutron powder diffraction, synchrotron X-ray powder diffraction, and electron diffraction data. The β-phase (stable between 132 and 153 °C) and γ-phase (stable between 153 to 306 °C) can be described as unusually complex superstructures of the double-perovskite structure (K2KAlF6) which result from noncooperative tilting of the AlF6 octahedra. The β-phase is tetragonal, space group I4/m, with lattice parameters of a = 13.3862(5) Å and c = 8.5617(3) Å (at 143 °C) and Z = 10. In this phase, one-fifth of the AlF6 octahedra are rotated about the c-axis by 45° while the other four-fifths remain untilted. The large 45° rotations result in edge sharing between these AlF6 octahedra and the neighboring K-centered polyhedra, resulting in pentagonal bipyramidal coordination for four-fifths of the K+ ions that reside on the B-sites of the perovskite structure. The remaining one-fifth of the K+ ions on the B-sites retain octahedral coordination. The γ-phase is orthorhombic, space group Fddd, with lattice parameters of a = 36.1276(4) Å, b = 17.1133(2) Å, and c = 12.0562(1) Å (at 225 °C) and Z = 48. In the γ-phase, one-sixth of the AlF6 octahedra are randomly rotated about one of two directions by 45° while the other five-sixths remain essentially untilted. These rotations result in two-thirds of the K+ ions on the B-site obtaining 7-fold coordination while the other one-third remain in octahedral coordination. The δ-phase adopts the ideal cubic double-perovskite structure, space group Fmm, with a = 8.5943(1) Å at 400 °C. However, pair distribution function analysis shows that locally the δ-phase is quite different from its long-range average crystal structure. The AlF6 octahedra undergo large-amplitude rotations which are accompanied by off-center displacements of the K+ ions that occupy the 12-coordinate A-sites.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Easton, Pa	Editor
	Language		Wos	000293493100052	Publication Date	2011-07-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0020-1669;1520-510X;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	4.857	Times cited	19	Open Access
	Notes				Approved	Most recent IF: 4.857; 2011 IF: 4.601
	Call Number	UA @ lucian @ c:irua:91131			Serial	1468
Permanent link to this record



	Author	Batuk, D.; Hadermann, J.; Abakumov, A.; Vranken, T.; Hardy, A.; van Bael, M.; Van Tendeloo, G.
	Title	Layered perovskite-like Pb₂Fe₂O₅ structure as a parent matrix for the nucleation and growth of crystallographic shear planes			Type	A1 Journal article
	Year	2011	Publication	Inorganic chemistry	Abbreviated Journal	Inorg Chem
	Volume	50	Issue	11	Pages	4978-4986
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The Pb2Fe2O5 compound with a layered intergrowth structure has been prepared by a solid-state reaction at 700 °C. The incommensurate compound crystallizes in a tetragonal system with a = 3.9037(2) Å, c = 3.9996(4) Å, and q = 0.1186(4)c*, or when treated as a commensurate approximant, a = 3.9047(2) Å, c = 36.000(3) Å, space group I4/mmm. The crystal structure of Pb2Fe2O5 was resolved from transmission electron microscopy data. Atomic coordinates and occupancies of the cation positions were estimated from high-angle annular dark-field scanning transmission electron microscopy data. Direct visualization of the positions of the oxygen atoms was possible using annular bright-field scanning transmission electron microscopy. The structure can be represented as an intergrowth of perovskite blocks and partially disordered blocks with a structure similar to that of the Bi2O2 blocks in Aurivillius-type phases. The A-cation positions at the border of the perovskite block and the cation positions in the Aurivillius-type blocks are jointly occupied by Pb2+ and Fe3+ cations, resulting in a layer sequence along the c axis: PbOFeO2PbOFeO2Pb7/8Fe1/8O1xFe5/8Pb3/8O2Fe5/8Pb3/8. Upon heating, the layered Pb2Fe2O5 structure transforms into an anion-deficient perovskite modulated by periodically spaced crystallographic shear (CS) planes. Considering the layered Pb2Fe2O5 structure as a parent matrix for the nucleation and growth of CS planes allows an explanation of the specific microstructure observed for the CS structures in the PbFeO system.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Easton, Pa	Editor
	Language		Wos	000290978400038	Publication Date	2011-04-29
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0020-1669;1520-510X;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	4.857	Times cited	16	Open Access
	Notes				Approved	Most recent IF: 4.857; 2011 IF: 4.601
	Call Number	UA @ lucian @ c:irua:90141			Serial	1809
Permanent link to this record



	Author	He, Z.; Maurice, J.-L.; Gohier, A.; Lee, C.S.; Pribat, D.; Cojocaru, C.S.
	Title	Iron catalysts for the growth of carbon nanofibers : Fe, Fe₃C or both?			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	24	Pages	5379-5387
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Iron is a widely used catalyst for the growth of carbon nanotubes (CNTs) or carbon nanofibers (CNFs) by catalytic chemical vapor deposition. However, both Fe and FeC compounds (generally, Fe3C) have been found to catalyze the growth of CNTs/CNFs, and a comparison study of their respective catalytic activities is still missing. Furthermore, the control of the crystal structure of iron-based catalysts, that is α-Fe or Fe3C, is still a challenge, which not only obscures our understanding of the growth mechanisms of CNTs/CNFs, but also complicates subsequent procedures, such as the removal of catalysts for better industrial applications. Here, we show a partial control of the phase of iron catalysts (α-Fe or Fe3C), obtained by varying the growth temperatures during the synthesis of carbon-based nanofibers/nanotubes in a plasma-enhanced chemical vapor deposition reactor. We also show that the structure of CNFs originating from Fe3C is bamboo-type, while that of CNFs originating from Fe is not. Moreover, we directly compare the growth rates of carbon-based nanofibers/nanotubes during the same experiments and find that CNFs/CNTs grown by α-Fe nanoparticles are longer than CNFs grown from Fe3C nanoparticles. The influence of the type of catalyst on the growth of CNFs is analyzed and the corresponding possible growth mechanisms, based on the different phases of the catalysts, are discussed.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000298197300014	Publication Date	2011-11-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0897-4756;1520-5002;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	9.466	Times cited	91	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:94297			Serial	1748
Permanent link to this record



	Author	Belik, A.A.; Abakumov, A.M.; Tsirlin, A.A.; Hadermann, J.; Kim, J.; Van Tendeloo, G.; Takayama-Muromachi, E.
	Title	Article Structure and magnetic properties of BiFe_0.75Mn_0.25O₃ perovskite prepared at ambient and high pressure			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	20	Pages	4505-4514
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Solid solutions of BiFe1xMnxO3 (0.0 ≤ x ≤ 0.4) were prepared at ambient pressure and at 6 GPa. The ambient-pressure (AP) phases crystallize in space group R3c similarly to BiFeO3. The high-pressure (HP) phases crystallize in space group R3c for x = 0.05 and in space group Pnma for 0.15 ≤ x ≤ 0.4. The structure of HP-BiFe0.75Mn0.25O3 was investigated using synchrotron X-ray powder diffraction, electron diffraction, and transmission electron microscopy. HP-BiFe0.75Mn0.25O3 has a PbZrO3-related √2ap × 4ap × 2√2ap (ap is the parameter of the cubic perovskite subcell) superstructure with a = 5.60125(9) Å, b = 15.6610(2) Å, and c = 11.2515(2) Å similar to that of Bi0.82La0.18FeO3. A remarkable feature of this structure is the unconventional octahedral tilt system, with the primary ab0a tilt superimposed on pairwise clockwise and counterclockwise rotations around the b-axis according to the oioi sequence (o stands for out-of-phase tilt, and i stands for in-phase tilt). The (FeMn)O6 octahedra are distorted, with one longer metaloxygen bond (2.222.23 Å) that can be attributed to a compensation for covalent BiO bonding. Such bonding results in the localization of the lone electron pair on Bi3+ cations, as confirmed by electron localization function analysis. The relationship between HP-BiFe0.75Mn0.25O3 and antiferroelectric structures of PbZrO3 and NaNbO3 is discussed. On heating in air, HP-BiFe0.75Mn0.25O3 irreversibly transforms to AP-BiFe0.75Mn0.25O3 starting from about 600 K. Both AP and HP phases undergo an antiferromagnetic ordering at TN ≈ 485 and 520 K, respectively, and develop a weak net magnetic moment at low temperatures. Additionally, ceramic samples of AP-BiFe0.75Mn0.25O3 show a peculiar phenomenon of magnetization reversal.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000295897400015	Publication Date	2011-09-29
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0897-4756;1520-5002;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	9.466	Times cited	57	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:93581			Serial	151
Permanent link to this record



	Author	Hadermann, J.; Abakumov, A.M.; Turner, S.; Hafideddine, Z.; Khasanova, N.R.; Antipov, E.V.; Van Tendeloo, G.
	Title	Solving the structure of Li ion battery materials with precession electron diffraction : application to Li₂CoPo₄F			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	15	Pages	3540-3545
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The crystal structure of the Li2CoPO4F high-voltage cathode for Li ion rechargeable batteries has been completely solved from precession electron diffraction (PED) data, including the location of the Li atoms. The crystal structure consists of infinite chains of CoO4F2 octahedra sharing common edges and linked into a 3D framework by PO4 tetrahedra. The chains and phosphate anions together delimit tunnels filled with the Li atoms. This investigation demonstrates that PED can be successfully applied for obtaining structural information on a variety of Li-containing electrode materials even from single micrometer-sized crystallites.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000293357100019	Publication Date	2011-07-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0897-4756;1520-5002;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	9.466	Times cited	46	Open Access
	Notes	Fwo; Bof			Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:90357			Serial	3053
Permanent link to this record



	Author	Kazakov, S.M.; Abakumov, A.M.; Perz-Mato, J.M.; Ovchinnikov, A.V.; Roslova, M.V.; Boltalin, A.I.; Morozov, I.V.; Antipov, E.V.; Van Tendeloo, G.
	Title	Uniform patterns of Fe-vacancy ordering in the K_x(Fe,Co)_2-ySe₂ superconductors			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	19	Pages	4311-4316
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The Fe-vacancy ordering patterns in the superconducting KxFe2ySe2 and nonsuperconducting Kx(Fe,Co)2ySe2 samples have been investigated by electron diffraction and high angle annular dark field scanning transmission electron microscopy. The Fe-vacancy ordering occurs in the ab plane of the parent ThCr2Si2-type structure, demonstrating two types of patterns. Superstructure I retains the tetragonal symmetry and can be described with the aI = bI = as√5 (as is the unit cell parameter of the parent ThCr2Si2-type structure) supercell and I4/m space group. Superstructure II reduces the symmetry to orthorhombic with the aII = as√2, bII = 2as√2 supercell and the Ibam space group. This type of superstructure is observed for the first time in KxFe2ySe2. The Fe-vacancy ordering is inhomogeneous: the disordered areas interleave with the superstructures I and II in the same crystallite. The observed superstructures represent the compositionally dependent uniform ordering patterns of two species (the Fe atoms and vacancies) on a square lattice. More complex uniform ordered configurations, including compositional stripes, can be predicted for different chemical compositions of the KxFe2ySe2 (0 < y < 0.5) solid solutions.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000295487800005	Publication Date	2011-09-13
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0897-4756;1520-5002;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	9.466	Times cited	20	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:92805			Serial	3810
Permanent link to this record



	Author	Dachraoui, W.; Yang, T.; Liu, C.; Ling, G.; Hadermann, J.; Van Tendeloo, G.; Llobet, A.; Greenblatt, M.
	Title	Short-range layered A-site ordering in double perovskites NaLaBB'O₆ (B = Mn, Fe; B' = Nb, Ta)			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	9	Pages	2398-2406
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The new compounds NaLaFeTaO6, NaLaFeNbO6, NaLaMnTaO6, and NaLaMnNbO6 have been synthesized and characterized with a combination of transmission electron microscopy, X-ray powder diffraction (XRPD), neutron powder diffraction (NPD), and magnetization measurements. Through electron microscopy study, a local layered order of the A-cations has been detected without the typical occurrence of rock salt order at the B-cation site. Satellite reflections in the electron diffraction related to the local layered order are not visible on the XRPD or NPD patterns. The occurrence of local layered order is supported by pair distribution function analysis, which also reveals the presence of uncorrelated displacements of the Nb and Ta cations. The octahedra are tilted according to the system a−b+a−, and the coordinates were refined from XRPD and NPD with a disordered cation distribution in the space group Pnma. The magnetic exchange interactions in NaLaFeTaO6 and NaLaFeNbO6 are antiferromagnetic, while they are ferromagnetic in NaLaMnTaO6 and NaLaMnNbO6. Long-range magnetic ordering is not observed down to 4 K for any of the compositions.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000290063600016	Publication Date	2011-04-14
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0897-4756;1520-5002;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	9.466	Times cited	14	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:89944			Serial	2996
Permanent link to this record



	Author	Rusakov, D.; Abakumov, A.M.; Yamaura, K.; Belik, A.A.; Van Tendeloo, G.; Takayama-Muromachi, E.
	Title	Structural evolution of the BiFeO₃-LaFeO₃ system			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	2	Pages	285-292
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The (1 − x)BiFeO3−xLaFeO3 system has been investigated and characterized by room-temperature and high-temperature laboratory and synchrotron powder X-ray diffraction, electron diffraction, high-resolution transmission electron microscopy, differential scanning calorimetry, and magnetization measurements. At room temperature, the ferroelectric R3c phase is observed for 0.0 ≤ x ≤ 0.10. The PbZrO3-related √2ap × 2√2ap × 4ap superstructure (where ap is the parameter of the cubic perovskite subcell) is observed for Bi0.82La0.18FeO3, while an incommensurately modulated phase is formed for 0.19 ≤ x ≤ 0.30 with the √2ap × 2ap × √2ap basic unit cell. The GdFeO3-type phase with space group Pnma (√2ap × 2ap × √2ap) is stable at 0.50 ≤ x ≤ 1. Bi0.82La0.18FeO3 has no detectable homogeneity range (space group Pnam, a = 5.6004(1) Å, b = 11.2493(3) Å, c = 15.6179(3) Å). The incommensurately modulated Bi0.75La0.25FeO3 structure was solved from synchrotron X-ray powder diffraction data (Imma(00γ)s00 superspace group, a = 5.5956(1) Å, b = 7.8171(1) Å, c = 5.62055(8) Å, q = 0.4855(4)c*, RP = 0.023, RwP = 0.033). In this structure, cooperative displacements of the Bi and O atoms occur, which order within the (AO) (where A = Bi, La) layers, resulting in an antipolar structure. Local fluctuations of the intralayer antipolar ordering are compensated by an interaction with the neighboring (AO) layers. A coupling of the antipolar displacements with the cooperative tilting distortion of the perovskite octahedral framework is proposed as the origin of the incommensurability. All the phases transform to the GdFeO3-type structure at high temperatures. Bi0.82La0.18FeO3 shows an intermediate PbZrO3-type phase with √2ap × 2√2ap × 2ap (space group Pbam; a = 5.6154(2) Å, b = 11.2710(4) Å, and c = 7.8248(2) Å at 570 K). The compounds in the compositional range of 0.18 ≤ x ≤ 0.95 are canted antiferromagnets.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000286160800021	Publication Date	2010-12-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0897-4756;1520-5002;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	9.466	Times cited	133	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:88650			Serial	3236
Permanent link to this record



	Author	Gélard, J.; Jehanathan, N.; Roussel, H.; Gariglio, S.; Lebedev, O.I.; Van Tendeloo, G.; Dubourdieu, C.
	Title	Off-stoichiometry effects on the crystalline and defect structure of hexagonal manganite REMnO₃ films (RE = Y, Er, Dy)			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	5	Pages	1232-1238
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The crystalline and defect structure of epitaxial hexagonal RExMnyO3 (RE = Er, Dy) films with varying cationic composition was investigated by X-ray diffraction and transmission electron microscopy. The films are composed of a strained layer at the interface with the substrate and of a relaxed layer on top of it. The critical thickness is of 10 to 25 nm. For Mn-rich films (or RE deficient), an off-stoichiometric composition maintaining the hexagonal LuMnO3-type structure is stabilized over a large range of the RE/Mn ratio (0.72−1.00), with no Mn-rich secondary phases observed. A linear dependence of the out-of-plane lattice parameter with RE/Mn is observed in this range. Out-of-phase boundary (OPB) extended defects are observed in all films and exhibit a local change in stoichiometry. Such a large solubility limit in the RE deficient region points toward the formation of vacancies on the RE site (RExMnO3−δ, with 0.72 ≤ x < 1), a phenomenon that is encountered in perovskite manganites such as LaxMnO3−δ (x < 1) and that may strongly impact the physical properties of hexagonal manganites.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000287767200022	Publication Date	2011-02-03
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0897-4756;1520-5002;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	9.466	Times cited	17	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:88649			Serial	2430
Permanent link to this record



	Author	Abakumov, A.M.; Batuk, D.; Hadermann, J.; Rozova, M.G.; Sheptyakov, D.V.; Tsirlin, A.A.; Niermann, D.; Waschowski, F.; Hemberger, J.; Van Tendeloo, G.; Antipov, E.V.
	Title	Antiferroelectric (Pb,Bi)_1-xFe_1+xO_3-y perovskites modulated by crystallographic shear planes			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	2	Pages	255-265
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	We demonstrate for the first time a possibility to vary the anion content in perovskites over a wide range through a long-range-ordered arrangement of crystallographic shear (CS) planes. Anion-deficient perovskites (Pb,Bi)1−xFe1+xO3−y with incommensurately modulated structures were prepared as single phases in the compositional range from Pb0.857Bi0.094Fe1.049O2.572 to Pb0.409Bi0.567Fe1.025O2.796. Using a combination of electron diffraction and high-resolution scanning transmission electron microscopy, we constructed a superspace model describing a periodic arrangement of the CS planes. The model was verified by refinement of the Pb0.64Bi0.32Fe1.04O2.675 crystal structure from neutron powder diffraction data ((3 + 1)D S.G. X2/m(α0γ), X = [1/2,1/2,1/2,1/2], a = 3.9082(1) Å, b = 3.90333(8) Å, c = 4.0900(1) Å, β = 91.936(2)°, q = 0.05013(4)a* + 0.09170(3)c* at T = 700 K, RP = 0.036, RwP = 0.048). The (Pb,Bi)1−xFe1+xO3−y structures consist of perovskite blocks separated by CS planes confined to nearly the (509)p perovskite plane. Along the CS planes, the perovskite blocks are shifted with respect to each other over the 1/2[110]p vector that transforms the corner-sharing connectivity of the FeO6 octahedra in the perovskite framework to an edge-sharing connectivity of the FeO5 pyramids at the CS plane, thus reducing the oxygen content. Variation of the chemical composition in the (Pb,Bi)1−xFe1+xO3−y series occurs mainly because of a changing thickness of the perovskite block between the interfaces, that can be expressed through the components of the q vector as Pb6γ+2αBi1−7γ−αFe1+γ−αO3−3γ−α. The Pb, Bi, and Fe atoms are subjected to strong displacements occurring in antiparallel directions on both sides of the perovskite blocks, resulting in an antiferroelectric-type structure. This is corroborated by the temperature-, frequency-, and field-dependent complex permittivity measurements. Pb0.64Bi0.32Fe1.04O2.675 demonstrates a remarkably high resistivity >0.1 T Ω cm at room temperature and orders antiferromagnetically below TN = 608(10) K.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000286160800018	Publication Date	2010-12-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0897-4756;1520-5002;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	9.466	Times cited	29	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:88651			Serial	136
Permanent link to this record