Simulation of field-induced molecular dissociation in atom-probe tomography: Identification of a neutral emission channel

Zanuttini, David; Blum, Ivan; Rigutti, Lorenzo; Vurpillot, F.; Douady, Julie; Jacquet, E.; Anglade, Pierre-Matthieu; Gervais, B.

doi:10.1103/physreva.95.061401

Cited by 46 publications

(45 citation statements)

References 27 publications

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“…As recently investigated by Zanuttini et al through a theoretical study of the dissociation of ZnO 2 + molecules in different dissociation channels containing charged and neutral species, dissociation can have an important role in atom probe measurements [28] . The dissociation of ZnO 2 + molecules can occur through different channels, one of which would form neutral O, and would explain the oxygen-poor composition found at low F eff in ZnO [1,4,28] . Moreover, as shown in ref.…”

Section: Identification Of Molecular Dissociation Channelsmentioning

confidence: 99%

“…Moreover, as shown in ref. [28] , such dissociations would take place too close to the specimen surface (at a distance a few ångströms from the tip) to be detected in the correlation histograms.…”

Section: Identification Of Molecular Dissociation Channelsmentioning

confidence: 99%

“…V 0 here is the DC voltage applied to the tip during this event and V d is the potential at which a dissociation event takes place. V d can be calculated from measured times-of-flight of the two fragments [7,9,26,28] . In Fig.…”

Section: Identification Of Molecular Dissociation Channelsmentioning

confidence: 99%

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Compositional accuracy of atom probe tomography measurements in GaN: Impact of experimental parameters and multiple evaporation events

et al. 2018

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A systematic study of the biases occurring in the measurement of the composition of GaN by Atom Probe Tomography was carried out, in which the role of surface electric field and laser pulse intensity has been investigated. Our data confirm that the electric field is the main factor influencing the measured composition, which exhibits a deficiency of N at low field and a deficiency of Ga at high field. The deficiency of Ga at high field is interpreted in terms of preferential evaporation of Ga. The detailed analysis of multiple evaporation events reveals that the measured composition is not affected by pile-up phenomena occurring in detection system. The analysis of correlation histograms yields the signature of the production of neutral N due to the dissociation of GaN ions. However, the amount of N neutral molecules that can be detected cannot account for the N deficiency found at low field. Therefore, we propose that further mechanisms of neutral N evaporation could be represented by dissociation reactions such as GaN→ Ga+ N and GaN→ Ga+ N.

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Section: Identification Of Molecular Dissociation Channelsmentioning

confidence: 99%

Section: Identification Of Molecular Dissociation Channelsmentioning

confidence: 99%

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Compositional accuracy of atom probe tomography measurements in GaN: Impact of experimental parameters and multiple evaporation events

et al. 2018

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“…These values are similar to those typically used in the literature to calculate post-ionisation probabilities [39] and correspond to ionization from the ground state, without accounting for the intense electrostatic field. This is expected to be valid to a first approximation, although the electronic states of the field evaporated ions are affected by the intense electrostatic field [47]. Following Kingham's approach [39], the probability for ionization and post-ionization were calculated as a function of the electric field, as plotted in figure 7(a).…”

Section: Laser Pulsingmentioning

confidence: 99%

Quantification of solute deuterium in titanium deuteride by atom probe tomography with both laser pulsing and high-voltage pulsing: influence of the surface electric field

et al. 2019

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Atom probe tomography (APT) has been increasingly used to investigate hydrogen embrittlement in metals due to its unique capacity for direct imaging of H atoms interacting with microstructural features. The quantitativeness of hydrogen measurements by APT is yet to be established in views of erroneous compositional measurements of bulk hydrides and the influence of spurious hydrogen, e.g. residual gas inside the analysis chamber. Here, we analyzed titanium deuteride (approx. 65.0 at%-66.6 at% D) in lieu of hydride to minimize the overlap with residual gas, both with laser pulsing and highvoltage (HV) pulsing. Strategies were deployed to prevent H pick-up during specimen fabrication, including preparing specimens at cryogenic temperature. The measured composition of deuterium by APT with laser pulsing decreases significantly with the applied laser pulse energy, which is interpreted with regards to the strength of the corresponding surface electrostatic field, as assessed by the evolution of charge-state ratio. In contrast, compositional analyses with HV pulsing are roughly independent of the applied experimental parameters, although approx. 15 at%-20 at% off the nominal composition. Aided by plotting paired mass-to-charge correlations, the mechanisms of composition bias in both pulsing modes are discussed. A special emphasis is placed on the local variations of the measured composition as a function of the local electric field across the specimen's surface, which is not uniform due to asymmetric heat distribution related to the localized laser absorption and the faceted nature of surface caused by the crystallographic structure. Our investigations demonstrate the challenges of quantitative analysis of solute deuterium by APT but nevertheless provide insight to achieving the best possible experimental protocol.

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“…Our results hint to the potential complementarity of APT with regards to techniques such as cryo-TEM and NMR for the structure and conventional mass spectrometry for the composition. APT’s capacity to interrogate individual objects is unique, but comes with added uncertainties regarding spatial and compositional accuracy, partly due to the low count statistics, complex specimen shapes during field evaporation and associated ion trajectories 63 , and the complex behaviour exhibited by molecular ions during their flight that can lead to their dissociation into fragments including neutral species 64 , 65 .…”

Section: Discussionmentioning

confidence: 99%

A near atomic-scale view at the composition of amyloid-beta fibrils by atom probe tomography

Rusitzka

Stephenson

Szczepaniak

et al. 2018

Sci Rep

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Amyloid-beta (Ab) proteins play an important role in a number of neurodegenerative diseases. Ab is found in senile plaques in brains of Alzeimer’s disease patients. The 42 residues of the monomer form dimers which stack to fibrils gaining several micrometers in length. Using Ab fibrils with 13C and 15N marker substitution, we developed an innovative approach to obtain insights to structural and chemical information of the protein. We deposited the modified protein fibrils to pre-sharped aluminium needles with >100-nm apex diameters and, using the position-sensitive mass-to-charge spectrometry technique of atom probe tomography, we acquired the chemically-resolved three dimensional information for every detected ion evaporated in small fragments from the protein. We also discuss the influence of experimental parameters such as pulse energy and pulse frequency of the used Laser beam which lead to differences in the size of the gained fragments, developing the capability of localising metal atom within Ab plaques.

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Simulation of field-induced molecular dissociation in atom-probe tomography: Identification of a neutral emission channel

Cited by 46 publications

References 27 publications

Compositional accuracy of atom probe tomography measurements in GaN: Impact of experimental parameters and multiple evaporation events

Compositional accuracy of atom probe tomography measurements in GaN: Impact of experimental parameters and multiple evaporation events

Quantification of solute deuterium in titanium deuteride by atom probe tomography with both laser pulsing and high-voltage pulsing: influence of the surface electric field

A near atomic-scale view at the composition of amyloid-beta fibrils by atom probe tomography

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