Blar i NTNU Open på forfatter "Van Helvoort, Antonius"
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In-situ observations of dislocation recovery and low angle boundary formation in deformed aluminium
Ånes, Håkon Wiik; Van Helvoort, Antonius; Marthinsen, Knut (Journal article; Peer reviewed, 2019)An experimental study of the recovery of dislocations and low angle boundary formation in aluminium is presented. By combining in-situ annealing with orientation mapping in the transmission electron microscope, maps of ... -
Moiré fringes in conductive atomic force microscopy
Richarz, Leonie; He, J.; Ludacka, Ursula; Bourret, E.; Yan, Z.; Van Helvoort, Antonius; Meier, Dennis (Journal article; Peer reviewed, 2023)Moiré physics plays an important role in characterization of functional materials and engineering of physical properties in general, ranging from strain-driven transport phenomena to superconductivity. Here, we report on ... -
Nanocrystal segmentation in scanning precession electron diffraction data
Bergh, Tina; Johnstone, D.N.; Crout, P; Høgås, Simon; Midgley, Paul A.; Holmestad, Randi; Vullum, Per Erik; Van Helvoort, Antonius (Journal article; Peer reviewed, 2019)Scanning precession electron diffraction (SPED) enables the local crystallography of materials to be probed on the nanoscale by recording a two‐dimensional precession electron diffraction (PED) pattern at every probe ... -
Observation of Electric-Field-Induced Structural Dislocations in a Ferroelectric Oxide
Evans, Donald; Småbråten, Didrik Rene; Holstad, Theodor Secanell; Vullum, Per Erik; Mosberg, Aleksander Buseth; Yan, Zewu; Bourret, Edith; Van Helvoort, Antonius; Selbach, Sverre Magnus; Meier, Dennis (Peer reviewed; Journal article, 2021)Dislocations are 1D topological defects with emergent electronic properties. Their low dimensionality and unique properties make them excellent candidates for innovative device concepts, ranging from dislocation-based ... -
Orientation dependent pinning of (sub)grains by dispersoids during recovery and recrystallization in an Al–Mn alloy
Ånes, Håkon Wiik; Van Helvoort, Antonius; Marthinsen, Knut (Peer reviewed; Journal article, 2023)The recrystallized grain size and texture in alloys can be controlled via the microchemistry state during thermomechanical processing. The influence of concurrent precipitation on recovery and recrystallization is here ... -
Origin of Leakage Currents and Nanowire-to-Nanowire Inhomogeneity in Radial p-i-n Junction GaAs Nanowire Array Solar Cells on Si
Mukherjee, Anjan; Ren, Dingding; Mosberg, Aleksander Buseth; Vullum, Per Erik; Van Helvoort, Antonius; Fimland, Bjørn Ove Myking; Weman, Helge (Journal article; Peer reviewed, 2023)To realize the promising potential of radial junction nanowire (NW) array-based solar cells, it is crucial to get physical insight into how the overall photoconversion efficiency (PCE) is impacted by the hole mask properties, ... -
Processing and indexing of electron backscatter patterns using open-source software
Ånes, Håkon Wiik; Hjelen, Jarle; Sørensen, Bjørn Eske; Van Helvoort, Antonius; Marthinsen, Knut (Peer reviewed; Journal article, 2020)A new method to increase the signal-to-noise ratio S/N of electron backscatter patterns (EBSPs) based upon principal component analysis (PCA) is presented. The PCA denoising method is applied to ten scans of EBSPs from the ... -
Scanning Precession Electron Diffraction and What We Get Out of Such Data in Studies of Aluminium Alloys
Thronsen, Elisabeth; Bergh, Tina; Christiansen, Emil; Thorsen, Thor Inge; Van Helvoort, Antonius; Holmestad, Randi (Peer reviewed; Journal article, 2022) -
Scanning Precession Electron Diffraction Study of Hybrid Precipitates in a 6xxx Series Aluminium Alloy
Sunde, Jonas Kristoffer; Johnstone, Duncan; Marioara, Calin Daniel; Van Helvoort, Antonius; Midgley, Paul A.; Holmestad, Randi (Journal article; Peer reviewed, 2017)Obtaining reliable and statistical assessment of nanoscale precipitates to link the microstructure with material properties is a primary objective of transmission electron microscopy (TEM) studies of agehardenable aluminium ... -
Scanning Precession Electron Diffraction to aid Aluminum Alloy Development
Sunde, Jonas Kristoffer; Christiansen, Emil; Thronsen, Elisabeth; Wenner, Sigurd; Marioara, Calin Daniel; Van Helvoort, Antonius; Holmestad, Randi (Peer reviewed; Journal article, 2019) -
Selective area grown ZnTe nanowires as the basis for quasi-one-dimensional CdTe-HgTe multishell heterostructures
Hajer, Jan; Mantei, Willi; Kessel, Maximilian; Brüne, Christoph; Wenner, Sigurd; Van Helvoort, Antonius; Buhmann, Hartmut; Molenkamp, Laurens W. (Peer reviewed; Journal article, 2020)Selective area growth is employed in the vapor-liquid-solid molecular beam epitaxy of ZnTe nanowire arrays. Full control over the location of the individual nanowires is achieved by defined positioning of the growth catalyst. ... -
Selective area growth of AlGaN nanopyramid arrays on graphene by metal-organic vapor phase epitaxy
Munshi, A Mazid; Kim, Dong-Chul; Heimdal, Carl Philip J; Heilmann, Martin; Christiansen, Silke; Vullum, Per Erik; Van Helvoort, Antonius; Weman, Helge (Journal article; Peer reviewed, 2018)Wide-bandgap group III-nitride semiconductors are of special interest for applications in ultraviolet light emitting diodes, photodetectors, and lasers. However, epitaxial growth of high-quality III-nitride semiconductors ... -
SiC crystalline micro bullets on bio-carbon based charcoal substrate
Jayakumari, Sethulakshmy; Vullum, Per Erik; Van Helvoort, Antonius; Tangstad, Merete (Peer reviewed; Journal article, 2020)Silicon carbide (SiC) micro bullets were grown on a bio-carbon based charcoal substrate, the morphology and crystal structure were analyzed. In order to collect the crystallographic details scanning electron microscopy ... -
Single-Mode Near-Infrared Lasing in a GaAsSb-Based Nanowire Superlattice at Room Temperature
Ren, Dingding; Ahtapodov, Lyubomir; Nilsen, Julie Stene; Yang, Jianfeng; Gustafsson, Anders; Huh, Junghwan; Conibeer, G; Van Helvoort, Antonius; Fimland, Bjørn-Ove; Weman, Helge (Journal article; Peer reviewed, 2018)Semiconductor nanowire lasers can produce guided coherent light emission with miniaturized geometry, bringing about new possibilities for a variety of applications including nanophotonic circuits, optical sensing, and ... -
Stabilisation of amorphous calcium phosphate in polyethylene glycol hydrogels
Schweikle, Manuel; Bjørnøy, Sindre Hove; Van Helvoort, Antonius; Haugen, Håvard Jostein; Sikorski, Pawel; Tiainen, Hanna (Journal article; Peer reviewed, 2019)Acellular polymer-calcium phosphate composites are promising bone graft materials. Hydrogels are suitable for providing a temporary matrix, while calcium phosphate minerals serve as ion depots for calcium and phosphate ... -
Structural Characterization of Natural Quartz by Scanning TEM
Busam, Jochen; Wenner, Sigurd; Muggerud, Astrid Marie; Van Helvoort, Antonius (Journal article; Peer reviewed, 2018)For quartz, despite its industrial importance and an extensive amount of research done on it, there are still open fundamental questions, e.g. regarding crystal defects, phase changes or damage mechanisms under ionizing ... -
The evolution of precipitate crystal structures in an Al-Mg-Si(-Cu) alloy studied by a combined HAADF-STEM and SPED approach
Sunde, Jonas Kristoffer; Marioara, Calin Daniel; Van Helvoort, Antonius; Holmestad, Randi (Journal article; Peer reviewed, 2018)This work presents a detailed investigation into the effect of a low Cu addition (0.01 at.%) on precipitation in an Al-0.80Mg-0.85Si alloy during ageing. The precipitate crystal structures were assessed by scanning ... -
The Third Dimension of Ferroelectric Domain Walls
Roede, Erik Dobloug; Shapovalov, Konstantin; Moran, Thomas; Mosberg, Aleksander Buseth; Yan, Zewu; Bourret, Edith; Cano, Andres; Huey, Bryan D.; Van Helvoort, Antonius; Meier, Dennis (Peer reviewed; Journal article, 2022)Ferroelectric domain walls are quasi-2D systems that show great promise for the development of nonvolatile memory, memristor technology, and electronic components with ultrasmall feature size. Electric fields, for example, ... -
Unsupervised machine learning applied to scanning precession electron diffraction data
Martineau, B. H.; Johnstone, D.N.; Van Helvoort, Antonius; Midgley, Paul A.; eggeman, A.S (Journal article; Peer reviewed, 2019)Scanning precession electron diffraction involves the acquisition of a two-dimensional precession electron diffraction pattern at every probe position in a two-dimensional scan. The data typically comprise many more ... -
Using FIB-SEM as a Platform for the Positioning and Correlated Characterization of III-V Nanowires
Mosberg, Aleksander Buseth; Ren, Dingding; Fauske, Vidar Tonaas; Fimland, Bjørn-Ove; Van Helvoort, Antonius (Journal article; Peer reviewed, 2018)