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Author Chen, J.J.; Wang, Q.; Meng, J.; Ke, X.; Van Tendeloo, G.; Bie, Y.Q.; Liu, J.; Liu, K.; Liao, Z.M.; Sun, D.; Yu, D.;
Title Photovoltaic effect and evidence of carrier multiplication in graphene vertical homojunctions with asymmetrical metal contacts Type A1 Journal article
Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
Volume 9 Issue 9 Pages (up) 8851-8858
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Graphene exhibits exciting potentials for high-speed wideband photodetection and high quantum efficiency solar energy harvest because of its broad spectral absorption, fast photoelectric response, and potential carrier multiplication. Although photocurrent can be generated near a metalgraphene interface in lateral devices, the photoactive area is usually limited to a tiny one-dimensional line-like interface region. Here, we report photoelectric devices based on vertical graphene two-dimensional homojunction, which is fabricated via vertically stacking four graphene monolayers with asymmetric metal contacts. The devices show excellent photovoltaic output with excitation wavelength ranging from visible light to mid-infrared. The wavelength dependence of the internal quantum efficiency gives direct evidence of the carrier multiplication effect in graphene. The simple fabrication process, easy scale-up, large photoresponsive active area, and broadband response of the vertical graphene device are very promising for practical applications in optoelectronics and photovoltaics.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000361935800023 Publication Date 2015-08-15
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 11 Open Access
Notes 246791 Countatoms Approved Most recent IF: 13.942; 2015 IF: 12.881
Call Number c:irua:127689 Serial 2615
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Author Goffin, A.-L.; Duquesne, E.; Raquez, J.-M.; Miltner, H.E.; Ke, X.; Alexandre, M.; Van Tendeloo, G.; van Mele, B.; Dubois, P.
Title From polyester grafting onto POSS nanocage by ring-opening polymerization to high performance polyester/POSS nanocomposites Type A1 Journal article
Year 2010 Publication Journal of materials chemistry Abbreviated Journal J Mater Chem
Volume 20 Issue 42 Pages (up) 9415-9422
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Polyester-grafted polyhedral oligomeric silsesquioxane (POSS) nanohybrids selectively produced by ring-opening polymerization of ε-caprolactone and L,L-lactide (A.-L. Goffin, E. Duquesne, S. Moins, M. Alexandre, Ph. Dubois, Eur. Polym. Journal, 2007, 43, 4103) were studied as masterbatches by melt-blending within their corresponding commercial polymeric matrices, i.e., poly(ε-caprolactone) (PCL) and poly(L,L-lactide) (PLA). For the sake of comparison, neat POSS nanoparticles were also dispersed in PCL and PLA. The objective was to prepare aliphatic polyester-based nanocomposites with enhanced crystallization behavior, and therefore, enhanced thermo-mechanical properties. Wide-angle X-ray scattering and transmission electron microscopy attested for the dispersion of individualized POSS nanoparticles in the resulting nanocomposite materials only when the polyester-grafted POSS nanohybrid was used as a masterbatch. The large impact of such finely dispersed (grafted) nanoparticles on the crystallization behavior for the corresponding polyester matrices was noticed, as evidenced by differential scanning calorimetry analysis. Indeed, well-dispersed POSS nanoparticles acted as efficient nucleating sites, significantly increasing the crystallinity degree of both PCL and PLA matrices. As a result, a positive impact on thermo-mechanical properties was highlighted by dynamic mechanical thermal analysis.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000283264500017 Publication Date 2010-06-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-9428;1364-5501; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited 42 Open Access
Notes Fwo; Iap-6 Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:85784 Serial 1284
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Author Yan, Y.; Zhou, X.; Jin, H.; Li, C.-Z.; Ke, X.; Van Tendeloo, G.; Liu, K.; Yu, D.; Dressel, M.; Liao, Z.-M.
Title Surface-Facet-Dependent Phonon Deformation Potential in Individual Strained Topological Insulator Bi2Se3 Nanoribbons Type A1 Journal article
Year 2015 Publication ACS nano Abbreviated Journal Acs Nano
Volume 9 Issue 9 Pages (up) 10244-10251
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Strain is an important method to tune the properties of topological insulators. For example, compressive strain can induce superconductivity in Bi2Se3 bulk material. Topological insulator nanostructures are the superior candidates to utilize the unique surface states due to the large surface to volume ratio. Therefore, it is highly desirable to monitor the local strain effects in individual topological insulator nanostructures. Here, we report the systematical micro-Raman spectra of single strained Bi2Se3 nanoribbons with different thicknesses and different surface facets, where four optical modes are resolved in both Stokes and anti-Stokes Raman spectral lines. A striking anisotropy of the strain dependence is observed in the phonon frequency of strained Bi2Se3 nanoribbons grown along the ⟨112̅0⟩ direction. The frequencies of the in-plane Eg2 and out-of-plane A1g1 modes exhibit a nearly linear blue-shift against bending strain when the nanoribbon is bent along the ⟨112̅0⟩ direction with the curved {0001} surface. In this case, the phonon deformation potential of the Eg2 phonon for 100 nm-thick Bi2Se3 nanoribbon is up to 0.94 cm–1/%, which is twice of that in Bi2Se3 bulk material (0.52 cm–1/%). Our results may be valuable for the strain modulation of individual topological insulator nanostructures.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Wos 000363915300079 Publication Date 2015-09-12
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 14 Open Access
Notes Y.Y. would like to thank Xuewen Fu for helpful discussions. This work was supported by MOST (Nos. 2013CB934600, 2013CB932602) and NSFC (Nos. 11274014, 11234001). Approved Most recent IF: 13.942; 2015 IF: 12.881
Call Number c:irua:129216 Serial 3963
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Author Wang, C.; Ke, X.; Wang, J.; Liang, R.; Luo, Z.; Tian, Y.; Yi, D.; Zhang, Q.; Wang, J.; Han, X.-F.; Van Tendeloo, G.; Chen, L.-Q.; Nan, C.-W.; Ramesh, R.; Zhang, J.
Title Ferroelastic switching in a layered-perovskite thin film Type A1 Journal article
Year 2016 Publication Nature communications Abbreviated Journal Nat Commun
Volume 7 Issue 7 Pages (up) 10636
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract A controllable ferroelastic switching in ferroelectric/multiferroic oxides is highly desirable due to the non-volatile strain and possible coupling between lattice and other order parameter in heterostructures. However, a substrate clamping usually inhibits their elastic deformation in thin films without micro/nano-patterned structure so that the integration of the non-volatile strain with thin film devices is challenging. Here, we report that reversible in-plane elastic switching with a non-volatile strain of approximately 0.4% can be achieved in layered-perovskite Bi2WO6 thin films, where the ferroelectric polarization rotates by 90 degrees within four in-plane preferred orientations. Phase-field simulation indicates that the energy barrier of ferroelastic switching in orthorhombic Bi2WO6 film is ten times lower than the one in PbTiO3 films, revealing the origin of the switching with negligible substrate constraint. The reversible control of the in-plane strain in this layered-perovskite thin film demonstrates a new pathway to integrate mechanical deformation with nanoscale electronic and/or magnetoelectronic applications.
Address Department of Physics, Beijing Normal University, 100875 Beijing, China
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Wos 000371020600002 Publication Date 2016-02-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-1723 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 12.124 Times cited 40 Open Access
Notes The work in Beijing Normal University is supported by the NSFC under contract numbers 51322207, 51332001 and 11274045. J.Z. also acknowledges the support from National Basic Research Program of China, under contract No. 2014CB920902. G.V.T. acknowledges the funding from the European Research Council under the Seventh Framework Program (FP7), ERC Advanced Grant No. 246791-COUNTATOMS. X.K. acknowledges the funding from NSFC (Grant No.11404016) and Beijing University of Technology (2015-RD-QB-19). J.W. acknowledges the funding from NSFC (Grant number 51472140). L.-Q.C. acknowledges the supporting by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award FG02-07ER46417. R.L. acknowledges Tsinghua National Laboratory for Information Science and Technology (TNList) Cross-discipline Foundation. Z.L. acknowledges the support from the NSFC (No.11374010 and No.11434009). Q.Z. and X.-F.H. acknowledge the funding support from NSFC (Grant No. 11434014). R.R. acknowledges support from the National Science Foundation (Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems) under grant number EEC-1160504. Approved Most recent IF: 12.124
Call Number c:irua:130978 Serial 4007
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Author Zhou, X.-G.; Yang, C.-Q.; Sang, X.; Li, W.; Wang, L.; Yin, Z.-W.; Han, J.-R.; Li, Y.; Ke, X.; Hu, Z.-Y.; Cheng, Y.-B.; Van Tendeloo, G.
Title Probing the electron beam-induced structural evolution of halide perovskite thin films by scanning transmission electron microscopy Type A1 Journal article
Year 2021 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 125 Issue 19 Pages (up) 10786-10794
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract A deep understanding of the fine structure at the atomic scale of halide perovskite materials has been limited by their sensitivity to the electron beam that is widely used for structural characterization. The sensitivity of a gamma-CsPbIBr2 perovskite thin film under electron beam irradiation is revealed by scanning transmission electron microscopy (STEM) through a universal large-range electron dose measurement, which is based on discrete single-electron events in the STEM mode. Our research indicates that the gamma-CsPbIBr2 thin film undergoes structural changes with increasing electron overall dose (e(-).A(-2)) rather than dose rate (e(-).A(-2).s(-1)), which suggests that overall dose is the key operative parameter. The electron beam-induced structural evolution of gamma-CsPbIBr2 is monitored by fine control of the electron beam dose, together with the analysis of high-resolution (S)TEM, diffraction, and energy-dispersive X-ray spectroscopy. Our results show that the gamma-CsPbIBr2 phase first forms an intermediate phase [e.g., CsPb(1-x)(IBr)((3-y))] with a superstructure of ordered vacancies in the pristine unit cell, while a fraction of Pb2+ is reduced to Pb-0. As the electron dose increases, Pb nanoparticles precipitate, while the remaining framework forms the Cs2IBr phase, accompanied by some amorphization. This work provides guidelines to minimize electron beam irradiation artifacts for atomic-resolution imaging on CsPbIBr2 thin films.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000655640900061 Publication Date 2021-05-11
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 Open Access Not_Open_Access
Notes Approved Most recent IF: 4.536
Call Number UA @ admin @ c:irua:179187 Serial 6880
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Author Cabana, L.; Gonzalez-Campo, A.; Ke, X.; Van Tendeloo, G.; Nunez, R.; Tobias, G.
Title Efficient Chemical Modification of Carbon Nanotubes with Metallacarboranes Type A1 Journal article
Year 2015 Publication Chemistry: a European journal Abbreviated Journal Chem-Eur J
Volume 21 Issue 21 Pages (up) 16792-16795
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract As-produced single-walled carbon nanotubes (SWCNTs) tend to aggregate in bundles due to pi-pi interactions. Several approaches are nowadays available to debundle, at least partially, the nanotubes through surface modification by both covalent and noncovalent approaches. Herein, we explore different strategies to afford an efficient covalent functionalization of SWCNTs with cobaltabisdicarbollide anions. Aberration-corrected HRTEM analysis reveals the presence of metallacarboranes along the walls of the SWCNTs. This new family of materials presents an outstanding water dispersibility that facilitates its processability for potential applications.
Address Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus Universitari de la UAB. 08193, Bellaterra (Spain). gerard.tobias@icmab.es
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000366501600011 Publication Date 2015-10-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0947-6539; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 5.317 Times cited 5 Open Access
Notes The research leading to these results received financial support from MINECO (MAT2014-53500-R; CTQ2013-44670-R), Generalitat de Catalunya (2014/SGR/149), and from the European Commission under the FP7 ITN Marie-Curie Network programme RADDEL (grant agreement 290023), the Integrated Infrastructure Initiative No. 262348 European Soft Matter Infrastructure (ESMI) and the European Research Council, ERC Grant No 246791-COUNTATOMS. A.G.C. thanks the CSIC for the JAE-DOC grant. Approved Most recent IF: 5.317; 2015 IF: 5.731
Call Number c:irua:129215 Serial 3964
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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 (up) 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
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Author Skaltsas, T.; Ke, X.; Bittencourt, C.; Tagmatarchis, N.
Title Ultrasonication induces oxygenated species and defects onto exfoliated graphene Type A1 Journal article
Year 2013 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 117 Issue 44 Pages (up) 23272-23278
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The effect of ultrasonication parameters, such as time and power applied, to exfoliate graphite in o-dichlorobenzene (o-DCB) and N-methyl-1,2-pyrrolidone (NMP) was examined. It was found that the concentration of graphene was higher in o-DCB, while its dispersibility was increased when sonication was applied for a longer period and/or at higher power. However, spectroscopic examination by X-ray photoelectron spectroscopy (XPS) revealed that ultrasonication causes defects and induces oxygen functional groups in the form of carboxylic acids and ethers/epoxides onto the graphene lattice. Additional proof for the latter arose from Raman, IR, and thermogravimetry studies. The carboxylic acids and ethers/epoxides onto exfoliated graphene were derived from air during ultrasonication and found independent of the solvent used for the exfoliation and the power and/or time ultrasonication applied. Quantitative evaluation of the amount of oxygenated species present on exfoliated graphene as performed by high-resolution XPS revealed that the relative oxygen percentage was higher when exfoliation was performed in NMP. Finally, the sonication time and/or power affected the oxygen content on exfoliated graphene, since extended ultrasonication resulted in a decrease in the oxygen content on exfoliated graphene, with a simultaneous increase of defected sp(3) carbon atoms.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000326845400090 Publication Date 2013-10-03
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 65 Open Access
Notes Approved Most recent IF: 4.536; 2013 IF: 4.835
Call Number UA @ lucian @ c:irua:112710 Serial 3797
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Author Hoek, M.; Coneri, F.; Poccia, N.; Renshaw Wang, X.; Ke, X.; Van Tendeloo, G.; Hilgenkamp, H.
Title Strain accommodation through facet matching in La1.85Sr0.15CuO4/Nd1.85Ce0.15CuO4 ramp-edge junctions Type A1 Journal article
Year 2015 Publication APL materials Abbreviated Journal Apl Mater
Volume 3 Issue 3 Pages (up) 086101
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Scanning nano-focused X-ray diffraction and high-angle annular dark-field scanning transmission electron microscopy are used to investigate the crystal structure of ramp-edge junctions between superconducting electron-doped Nd1.85Ce0.15CuO4 and superconducting hole-doped La1.85Sr0.15CuO4 thin films, the latter being the top layer. On the ramp, a new growth mode of La1.85Sr0.15CuO4 with a 3.3° tilt of the c-axis is found. We explain the tilt by developing a strain accommodation model that relies on facet matching, dictated by the ramp angle, indicating that a coherent domain boundary is formed at the interface. The possible implications of this growth mode for the creation of artificial domains in morphotropic materials are discussed.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000360656800009 Publication Date 2015-08-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2166-532X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.335 Times cited 4 Open Access
Notes 312483 Esteem2; 246791 Countatoms; esteem2_jra2 Approved Most recent IF: 4.335; 2015 IF: NA
Call Number c:irua:127690 c:irua:127690 Serial 3163
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Author Schulze, A.; Hantschel, T.; Dathe, A.; Eyben, P.; Ke, X.; Vandervorst, W.
Title Electrical tomography using atomic force microscopy and its application towards carbon nanotube-based interconnects Type A1 Journal article
Year 2012 Publication Nanotechnology Abbreviated Journal Nanotechnology
Volume 23 Issue 30 Pages (up) 305707
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The fabrication and integration of low-resistance carbon nanotubes (CNTs) for interconnects in future integrated circuits requires characterization techniques providing structural and electrical information at the nanometer scale. In this paper we present a slice-and-view approach based on electrical atomic force microscopy. Material removal achieved by successive scanning using doped ultra-sharp full-diamond probes, manufactured in-house, enables us to acquire two-dimensional (2D) resistance maps originating from different depths (equivalently different CNT lengths) on CNT-based interconnects. Stacking and interpolating these 2D resistance maps results in a three-dimensional (3D) representation (tomogram). This allows insight from a structural (e.g. size, density, distribution, straightness) and electrical point of view simultaneously. By extracting the resistance evolution over the length of an individual CNT we derive quantitative information about the resistivity and the contact resistance between the CNT and bottom electrode.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000306333500029 Publication Date 2012-07-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-4484;1361-6528; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.44 Times cited 29 Open Access
Notes Approved Most recent IF: 3.44; 2012 IF: 3.842
Call Number UA @ lucian @ c:irua:100750 Serial 895
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Author Llobet, E.; Espinosa, E.H.; Sotter, E.; Ionescu, R.; Vilanova, X.; Torres, J.; Felten, A.; Pireaux, J.J.; Ke, X.; Van Tendeloo, G.; Renaux, F.; Paint, Y.; Hecq, M.; Bittencourt, C.;
Title Carbon nanotube TiO2 hybrid films for detecting traces of O2 Type A1 Journal article
Year 2008 Publication Nanotechnology Abbreviated Journal Nanotechnology
Volume 19 Issue 37 Pages (up) 375501-375511
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Hybrid titania films have been prepared using an adapted sol-gel method for obtaining well-dispersed hydrogen plasma-treated multiwall carbon nanotubes in either pure titania or Nb-doped titania. The drop-coating method has been used to fabricate resistive oxygen sensors based on titania or on titania and carbon nanotube hybrids. Morphology and composition studies have revealed that the dispersion of low amounts of carbon nanotubes within the titania matrix does not significantly alter its crystallization behaviour. The gas sensitivity studies performed on the different samples have shown that the hybrid layers based on titania and carbon nanotubes possess an unprecedented responsiveness towards oxygen (i.e. more than four times higher than that shown by optimized Nb-doped TiO(2) films). Furthermore, hybrid sensors containing carbon nanotubes respond at significantly lower operating temperatures than their non-hybrid counterparts. These new hybrid sensors show a strong potential for monitoring traces of oxygen (i.e. <= 10 ppm) in a flow of CO(2), which is of interest for the beverage industry.
Address
Corporate Author Thesis
Publisher Place of Publication Bristol Editor
Language Wos 000258385600014 Publication Date 2008-08-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0957-4484;1361-6528; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.44 Times cited 48 Open Access
Notes Pai Approved Most recent IF: 3.44; 2008 IF: 3.446
Call Number UA @ lucian @ c:irua:103083 Serial 282
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