Dissociative electron attachment to the complexation ligands hexafluoroacetylacetone, trifluoroacetylacetone and acetylacetone; a comparative experimental and theoretical study

Ómarsson, Benedikt; Engmann, Sarah; Ingólfsson, Oddur

doi:10.1039/c4ra04451g

Cited by 13 publications

(15 citation statements)

References 46 publications

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“…DEA to acetone 29,30 has been investigated before but only one study exists for acetylacetone. 31 The highest DEA yields have been obtained for electrons with kinetic energy E 0 close to the threshold for desorption, the latter seen in Fig. 5.…”

Section: Dissociative Ionization and Electron Attachment To Acetone A...mentioning

confidence: 86%

Acetone and the precursor ligand acetylacetone: distinctly different electron beam induced decomposition?

Warneke

Dorp

Rudolf

et al. 2015

Phys. Chem. Chem. Phys.

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In focused electron beam induced deposition (FEBID) acetylacetone plays a role as a ligand in metal acetylacetonate complexes. As part of a larger effort to understand the chemical processes in FEBID, the electron-induced reactions of acetylacetone were studied both in condensed layers and in the gas phase and compared to those of acetone. X-ray photoelectron spectroscopy (XPS) shows that the electron-induced decomposition of condensed acetone layers yields a non-volatile hydrocarbon residue while electron irradiation of acetylacetone films produces a non-volatile residue that contains not only much larger amounts of carbon but also significant amounts of oxygen. Electron-stimulated desorption (ESD) and thermal desorption spectrometry (TDS) measurements reveal striking differences in the decay kinetics of the layers. In particular, intact acetylacetone suppresses the desorption of volatile products. Gas-phase studies of dissociative electron attachment and electron impact ionization suggest that this effect cannot be traced back to differences in the initial fragmentation reactions of the isolated molecules but is due to subsequent dissociation processes and to an efficient reaction of released methyl radicals with adjacent acetylacetone molecules. These results could explain the incorporation of large amounts of ligand material in deposits fabricated by FEBID processes using acetylacetonate complexes.

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Section: Dissociative Ionization and Electron Attachment To Acetone A...mentioning

confidence: 86%

Acetone and the precursor ligand acetylacetone: distinctly different electron beam induced decomposition?

Warneke

Dorp

Rudolf

et al. 2015

Phys. Chem. Chem. Phys.

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“…It should, however, be noted that the treatment here is simplified to a quasi-diatomic model and molecular rearrangement and formation of new bonds upon electron capture can in some cases lead to considerably more fragmentation with fairly high cross sections at low incident energies. Good examples of such reactions are the extensive fragmentation of tetrafluorophenol and tetrafluoroaniline [ 35 ] as well as that of the commonly used FEBID precursor ligands tri- and hexafluoroacetylacetone [ 36 ]. In each of these cases, low energy electron attachment leads to the formation of neutral HF, which in turn releases the 5.9 eV HF BDE [ 37 ] and promotes further fragmentation of the parent molecule.…”

Section: Reviewmentioning

confidence: 99%

The role of low-energy electrons in focused electron beam induced deposition: four case studies of representative precursors

Thorman¹,

P²,

Fairbrother³

et al. 2015

Beilstein J. Nanotechnol.

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148

215

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SummaryFocused electron beam induced deposition (FEBID) is a single-step, direct-write nanofabrication technique capable of writing three-dimensional metal-containing nanoscale structures on surfaces using electron-induced reactions of organometallic precursors. Currently FEBID is, however, limited in resolution due to deposition outside the area of the primary electron beam and in metal purity due to incomplete precursor decomposition. Both limitations are likely in part caused by reactions of precursor molecules with low-energy (<100 eV) secondary electrons generated by interactions of the primary beam with the substrate. These low-energy electrons are abundant both inside and outside the area of the primary electron beam and are associated with reactions causing incomplete ligand dissociation from FEBID precursors. As it is not possible to directly study the effects of secondary electrons in situ in FEBID, other means must be used to elucidate their role. In this context, gas phase studies can obtain well-resolved information on low-energy electron-induced reactions with FEBID precursors by studying isolated molecules interacting with single electrons of well-defined energy. In contrast, ultra-high vacuum surface studies on adsorbed precursor molecules can provide information on surface speciation and identify species desorbing from a substrate during electron irradiation under conditions more representative of FEBID. Comparing gas phase and surface science studies allows for insight into the primary deposition mechanisms for individual precursors; ideally, this information can be used to design future FEBID precursors and optimize deposition conditions. In this review, we give a summary of different low-energy electron-induced fragmentation processes that can be initiated by the secondary electrons generated in FEBID, specifically, dissociative electron attachment, dissociative ionization, neutral dissociation, and dipolar dissociation, emphasizing the different nature and energy dependence of each process. We then explore the value of studying these processes through comparative gas phase and surface studies for four commonly-used FEBID precursors: MeCpPtMe3, Pt(PF3)4, Co(CO)3NO, and W(CO)6. Through these case studies, it is evident that this combination of studies can provide valuable insight into potential mechanisms governing deposit formation in FEBID. Although further experiments and new approaches are needed, these studies are an important stepping-stone toward better understanding the fundamental physics behind the deposition process and establishing design criteria for optimized FEBID precursors.

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“…Such processes can be both bond and site selective [2]. This selectivity is of high importance, e.g., in chemical lithography [3], nanofabrication [4,5] and for modification and functionalization of the surfaces [6,7]. Besides technological applications this specificity is relevant for radiation chemistry [8].…”

Section: Introductionmentioning

confidence: 99%

Electron driven processes in sulphur containing compounds CH3SCH3 and CH3SSCH3

Kopyra

Władziński

2015

Eur. Phys. J. D

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Abstract. Dissociative electron attachment to gas phase dimethyl sulphide (CH3SCH3) and dimethyl disulphide (CH3SSCH3) has been studied by means of a crossed beams apparatus. Cleavage of the C-S bond within CH3SCH3 and the S-S bond within CH3SSCH3 is observed within a resonance in the energy range below 2 eV and visible preferentially via the appearance of the fragment CH2S− . The striking finding is that the intensity of CH2S − generated from CH3SSCH3 is more than two orders of magnitude higher than the intensity of the respective anionic fragment generated from CH3SCH3. Our results clearly demonstrate that the CH3SSCH3 molecule, which contains disulphide bridge is substantially more sensitive towards electron attachment resulting mainly in dissociation along the S-S bridge.

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Dissociative electron attachment to the complexation ligands hexafluoroacetylacetone, trifluoroacetylacetone and acetylacetone; a comparative experimental and theoretical study

Abstract: Influence of fluorination on the negative ion resonances and dissociation dynamics in electron attachment to acetylacetone, trifluoroacetylacetone and hexafluoroacetylacetone are explored through calculations and experiments.

Cited by 13 publications

References 46 publications

Acetone and the precursor ligand acetylacetone: distinctly different electron beam induced decomposition?

Acetone and the precursor ligand acetylacetone: distinctly different electron beam induced decomposition?

The role of low-energy electrons in focused electron beam induced deposition: four case studies of representative precursors

Electron driven processes in sulphur containing compounds CH3SCH3 and CH3SSCH3

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