X-ray undulator beamline BW1 at DORIS III

Frahm, R.; Weigelt, J.; Meyer, G. De; Materlik, G.

doi:10.1063/1.1146466

Cited by 90 publications

(64 citation statements)

References 3 publications

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“…These experiments were performed at the UHV setups at the beamlines ID 32 [24,25] at ESRF (Grenoble, France) and BW1 [26] at Hasylab (Hamburg, Germany).…”

Section: X-ray Standing Waves (Xsw)mentioning

confidence: 99%

Mg and Si dopant incorporation and segregation in GaN

Schmidt

Siebert

Flege

et al. 2011

Physica Status Solidi (b)

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The surface segregation of Mg and Si dopant species and their atomic incorporation sites in GaN films grown by metal-organic vapour phase epitaxy (MOVPE) on sapphire (0001) substrates have been analysed by X-ray photoemission spectro-microscopy and X-ray standing waves (XSW). As revealed by spectro-microscopy, both Mg and Si tend to segregate to the surface. In case of Mg, an enhanced surface dopant concentration is found even after sputter-removal of several tens of nanometres, which confirms a segregation mechanism proposed earlier [S. Figge et al., Appl. Phys. Lett. 81, 4748 (2002)]. Si doping has been found to result in the formation of facetted grooves in the GaN films. The surface silicon concentration at the facets is determined to be about 2.5 times higher as compared to the planar (0001) surface by micro-spectroscopy. XSW results show that with increasing Mg dopant concentration, non-substitutional lattice sites are progressively occupied. The results can quantitatively be explained by Mg atoms incorporated in an anti-bixbyite-like structure and is related to inversion domain boundaries. For Si doping, no evidence is found for the occupation of non-substitutional sites. However, a decrease in crystal quality is observed with increasing Si concentration.X-ray photoemission micrograph of a Si doped GaN film showing a facetted groove at the lower left corner of the image. The local spectra (see inset) reveal Si enrichment at the facets.

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“…These experiments were performed at the UHV setups at the beamlines ID 32 [24,25] at ESRF (Grenoble, France) and BW1 [26] at Hasylab (Hamburg, Germany).…”

Section: X-ray Standing Waves (Xsw)mentioning

confidence: 99%

Mg and Si dopant incorporation and segregation in GaN

Schmidt

Siebert

Flege

et al. 2011

Physica Status Solidi (b)

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“…The X-ray absorption experiments were performed at the X-ray undulator beamline BW1 [12] at the DORIS III storage ring at HASYLAB (Hamburg, Germany) operating with 4.45 GeV positrons and injection currents of about 150 mA. The incident monochromatic X-ray beam from a Si(111) double-crystal monochromator with an energy resolution of about 0.9 eV was collimated to a vertical size of about 240 m and 10 mm horizontally.…”

Section: Methodsmentioning

confidence: 99%

Reflection mode XAFS at the Ti Kedge of Lithium Intercalated TiO2 Electrodes

et al. 2005

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Lithium intercalation and deintercalation in crystalline TiO 2 -electrodes (rutile and anatase modifications) was investigated ex situ using grazing incidence reflection mode X-ray absorption spectroscopy in a specialized cell which permits the removal of the electrolyte and the subsequent measurement of grazing incidence X-ray absorption spectra under a protecting noble gas atmosphere. Small changes observed in near edge X-ray absorption spectra indicated that the Ti 4+ ions are reduced by the electrochemical lithiation, depending on the TiO 2 modification, Ti 3.5+ states as well as Ti 3+ states are observed for rutile and anatase, respectively. Angle dependent experiments reveal that the intercalation is not complete for rutile, while anatase seems to be fully intercalated. In addition, a certain amount of Li remains in the anatase electrode after a complete intercalation -deintercalation cycle. The results suggest that Li-ions are generally accumulated at the electrode/electrolyte interface during both intercalation and deintercalation.

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“…Synchrotron grazing incidence X-ray diffraction (GIXD) data collection was performed with a liquid surface diffractometer at the undulator beamline BW1 which was located in the synchrotron radiation research laboratory HASYLAB at DESY (Hamburg, Germany) [9,10]. GIXD measurements were performed using a Langmuir trough with an area of 480 cm 2 placed in an air-tight aluminum container with Kapton windows.…”

Section: Synchrotron Grazing Incidence X-ray Diffractionmentioning

confidence: 99%

Structural Characterization of Self-Organized Mono- and Multilayers of Partly Fluorinated Polydialkoxyphosphazenes at the Air/Water Interface

et al. 2017

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Abstract.We report studies of the collapse of monolayers of mesomorphic poly [bis-(2,2,3,3,4,4,5,5-octafluoropentoxy)phosphazene] and poly [bis-(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptoxy)phosphazene]. The structure of the films has been examined at different stages of the collapse process by synchrotron grazing incidence X-ray diffraction. Surface pressure-surface area isotherms show that these films undergo a stepwise collapse with formation of multilayers. Grazing incidence X-ray diffraction reveals only one diffraction peak for the monolayer as well as for multilayers of the two polymers studied, which corresponds to an in-plane interchain spacing d = 15.2±0.1˚Å and 17.6±0.5˚Å, respectively. The in-plane correlation length ξxy reaches ca. 500 Å for PFP-C5 (33 macromolecules) and ca. 400 Å for PFP-C7 (23 macromolecules), implying a certain mesoscale order similar to a quasi-long-range one.

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X-ray undulator beamline BW1 at DORIS III

Cited by 90 publications

References 3 publications

Mg and Si dopant incorporation and segregation in GaN

Mg and Si dopant incorporation and segregation in GaN

Reflection mode XAFS at the Ti Kedge of Lithium Intercalated TiO2 Electrodes

Structural Characterization of Self-Organized Mono- and Multilayers of Partly Fluorinated Polydialkoxyphosphazenes at the Air/Water Interface

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