Specific Process Knowledge/Characterization/XPS/NexsaOverview: Difference between revisions
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| Surface composition analysis by low-energy ion scattering||Publication, background||H H Brongersma||[http://apps.webofknowledge.com.proxy.findit.dtu.dk/CitedFullRecord.do?product=WOS&colName=WOS&SID=F6P8vdNQigRKywglhCq&search_mode=CitedFullRecord&isickref=WOS:000245323100001&cacheurlFromRightClick=no link]||||||X||||||||||<span title="Low-energy ion scattering (LEIS) is an analytical tool that provides information on the atomic composition of the outer surface, when noble gas ions are used as projectiles. In fact, quantitative composition analysis is currently done on a huge variety of materials, including catalysts and organic materials. The information on the surface composition is contained in the signal of backscattered ions (typically 1–3 keV He+, Ne+). In order to translate the LEIS signal to an elemental surface concentration all factors determining the LEIS signal must be known. These are in particular the scattering cross section and the ion fraction of the backscattered particles. The scattering cross section, which is due to the screened electrostatic potential between target atom and projectile, is well-known for the prevailing conditions of LEIS. It is an intriguing fact that, despite the large quantity of successful applications, the charge exchange processes in LEIS are not yet fully understood. It is e.g. not known why in LEIS for a given atomic species on the surface the signal usually does not depend on which other species are present (absence of matrix effects). Significant progress has recently been made in the understanding of the underlying charge exchange processes. Therefore, the aim of this review is twofold: on the one hand, to summarize the present understanding of the factors that determine the ion fraction of the scattered projectiles in LEIS, i.e. charge exchange processes. On the other hand, to summarize how quantitative surface composition analysis can be accomplished. In addition, we critically review publications that deal with surface composition analysis by LEIS, and analyze in which cases and by what means this was achieved and where and why it was successful or failed. After reading this review the reader will be able to deal with the pitfalls encountered in LEIS and to choose preferred experimental conditions for quantitative surface composition analysis.">Abstract</span> | | Surface composition analysis by low-energy ion scattering||Publication, background||H H Brongersma||[http://apps.webofknowledge.com.proxy.findit.dtu.dk/CitedFullRecord.do?product=WOS&colName=WOS&SID=F6P8vdNQigRKywglhCq&search_mode=CitedFullRecord&isickref=WOS:000245323100001&cacheurlFromRightClick=no link]||||||X||||||||||<span title="Low-energy ion scattering (LEIS) is an analytical tool that provides information on the atomic composition of the outer surface, when noble gas ions are used as projectiles. In fact, quantitative composition analysis is currently done on a huge variety of materials, including catalysts and organic materials. The information on the surface composition is contained in the signal of backscattered ions (typically 1–3 keV He+, Ne+). In order to translate the LEIS signal to an elemental surface concentration all factors determining the LEIS signal must be known. These are in particular the scattering cross section and the ion fraction of the backscattered particles. The scattering cross section, which is due to the screened electrostatic potential between target atom and projectile, is well-known for the prevailing conditions of LEIS. It is an intriguing fact that, despite the large quantity of successful applications, the charge exchange processes in LEIS are not yet fully understood. It is e.g. not known why in LEIS for a given atomic species on the surface the signal usually does not depend on which other species are present (absence of matrix effects). Significant progress has recently been made in the understanding of the underlying charge exchange processes. Therefore, the aim of this review is twofold: on the one hand, to summarize the present understanding of the factors that determine the ion fraction of the scattered projectiles in LEIS, i.e. charge exchange processes. On the other hand, to summarize how quantitative surface composition analysis can be accomplished. In addition, we critically review publications that deal with surface composition analysis by LEIS, and analyze in which cases and by what means this was achieved and where and why it was successful or failed. After reading this review the reader will be able to deal with the pitfalls encountered in LEIS and to choose preferred experimental conditions for quantitative surface composition analysis.">Abstract</span> | ||
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| Monitoring surface metal oxide catalytic active sites with Raman spectroscopy||Publication, review||I E Wachs||[http://apps.webofknowledge.com.proxy.findit.dtu.dk/CitedFullRecord.do?product=WOS&colName=WOS&SID=F6P8vdNQigRKywglhCq&search_mode=CitedFullRecord&isickref=WOS:000284267000027 link]||||||||||X||||Metal oxides||<span title="The molecular aspect of the Raman vibrational selection rules allows for the molecular structural and reactivity determinations of metal oxide catalytic active sites in all types of oxide catalyst systems (supported metal oxides, zeolites, layered hydroxides, polyoxometalates (POMs), bulk pure metal oxides, bulk mixed oxides and mixed oxide solid solutions). The molecular structural and reactivity determinations of metal oxide catalytic active sites are greatly facilitated by the use of isotopically labeled molecules. The ability of Raman spectroscopy to (1) operate in all phases (liquid, solid, gas and their mixtures), (2) operate over a very wide temperature (273 degC to | | Monitoring surface metal oxide catalytic active sites with Raman spectroscopy||Publication, review||I E Wachs||[http://apps.webofknowledge.com.proxy.findit.dtu.dk/CitedFullRecord.do?product=WOS&colName=WOS&SID=F6P8vdNQigRKywglhCq&search_mode=CitedFullRecord&isickref=WOS:000284267000027 link]||||||||||X||||Metal oxides||<span title="The molecular aspect of the Raman vibrational selection rules allows for the molecular structural and reactivity determinations of metal oxide catalytic active sites in all types of oxide catalyst systems (supported metal oxides, zeolites, layered hydroxides, polyoxometalates (POMs), bulk pure metal oxides, bulk mixed oxides and mixed oxide solid solutions). The molecular structural and reactivity determinations of metal oxide catalytic active sites are greatly facilitated by the use of isotopically labeled molecules. The ability of Raman spectroscopy to (1) operate in all phases (liquid, solid, gas and their mixtures), (2) operate over a very wide temperature (273 degC to 1000 degC) and pressure (UHV to c100 atm) range, and (3) provide molecular level information about metal oxides makes Raman spectroscopy the most informative characterization technique for understanding the molecular structure and surface chemistry of the catalytic active sites present in metal oxide heterogeneous catalysts. The recent use of hyphenated Raman spectroscopy instrumentation (e.g., Raman–IR, Raman–UV-vis, Raman–EPR) and the operando Raman spectroscopy methodology (e.g., Raman–MS and Raman–GC) is allowing for the establishment of direct structure–activity/selectivity relationships that will have a significant impact on catalysis science in this decade. Consequently, this critical review will show the growth in the use of Raman spectroscopy in heterogeneous catalysis research, for metal oxides as well as metals, is poised to continue to exponentially grow in the coming years."> Abstract</span> | ||
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| Diffusion of In0.53Ga0.47As elements through hafnium oxide during post deposition annealing||Publication||W Cabrera||[http://apps.webofknowledge.com.proxy.findit.dtu.dk/CitedFullRecord.do?product=WOS&colName=WOS&SID=F6P8vdNQigRKywglhCq&search_mode=CitedFullRecord&isickref=WOS:000329838800016 link]||X||||X||||||TEM||HfO2, InGaAs, ALD||<span title="Diffusion of indium through HfO2 after post deposition annealing in N2 or forming gas environments is observed in HfO2/In0.53Ga0.47As stacks by low energy ion scattering and X-ray photo electron spectroscopy and found to be consistent with changes in interface layer thickness observed by transmission electron microscopy. Prior to post processing, arsenic oxide is detected at the surface of atomic layer deposition-grown HfO2 and is desorbed upon annealing at 350 degree C. Reduction of the interfacial layer thickness and potential densification of HfO2, resulting from indium diffusion upon annealing, is confirmed by an increase in capacitance."> Abstract</span> | | Diffusion of In0.53Ga0.47As elements through hafnium oxide during post deposition annealing||Publication||W Cabrera||[http://apps.webofknowledge.com.proxy.findit.dtu.dk/CitedFullRecord.do?product=WOS&colName=WOS&SID=F6P8vdNQigRKywglhCq&search_mode=CitedFullRecord&isickref=WOS:000329838800016 link]||X||||X||||||TEM||HfO2, InGaAs, ALD||<span title="Diffusion of indium through HfO2 after post deposition annealing in N2 or forming gas environments is observed in HfO2/In0.53Ga0.47As stacks by low energy ion scattering and X-ray photo electron spectroscopy and found to be consistent with changes in interface layer thickness observed by transmission electron microscopy. Prior to post processing, arsenic oxide is detected at the surface of atomic layer deposition-grown HfO2 and is desorbed upon annealing at 350 degree C. Reduction of the interfacial layer thickness and potential densification of HfO2, resulting from indium diffusion upon annealing, is confirmed by an increase in capacitance."> Abstract</span> | ||