Nanosession: Advanced Spectroscopy and Scattering

Gitteröffnung durch reduktive kovalente Volumen‐Funktionalisierung von schwarzem Phosphor

Eine chemisch-reduktive Volumen-Funktionalisierung von dünnlagigem schwarzem Phosphor (BP) gelang unter Verwendung von BP-Interkalationsverbindungen. Durch eine effektive reduktive Aktivierung wurde die kovalente Funktionalisierung des geladenen BP mit Alkylhalogeniden erzielt, wobei eine Öffnung des BP-Gitters und ein höherer Funktionalisierungsgrad als bei neutralen Reaktionsrouten resultieren.

Interface properties of magnetic tunnel junctionLa0.7Sr0.3MnO3/SrTiO3superlattices studied by standing-wave excited photoemission spectroscopy

The chemical and electronic-structure profiles of magnetic tunnel junction (MTJ) La0.7Sr0.3MnO3/SrTiO3 (LSMO/STO) superlattices have been quantitatively determined via soft and hard x-ray standing-wave excited photoemission, x-ray absorption and x-ray reflectivity, in conjunction with x-ray optical and core-hole multiplet theoretical modeling. Epitaxial superlattice samples consisting of 48 and 120 bilayers of LSMO and STO, each nominally four unit cells thick, and still exhibiting LSMO ferromagnetism, were studied. By varying the incidence angle around the superlattice Bragg condition, the standing wave was moved vertically through the interfaces. By comparing experiment to x-ray optical c…

Band Gap and Electronic Structure of an Epitaxial, SemiconductingCr0.80Al0.20Thin Film

This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and the Nanotechnology Network Project, MEXT, Japan. C. Papp and B. Balke thank the Humboldt foundation for support. Calculations were done at the Cornell Nanoscale Facility, part of the National Nanotechnology Infrastructure Network (NNIN) funded by NSF. HXPS experiments were approved at the NIMS Beamline Station (Proposal No. 2009A4906)

Probing bulk electronic structure with hard X-ray angle-resolved photoemission.

Traditional ultraviolet/soft X-ray angle-resolved photoemission spectroscopy (ARPES) may in some cases be too strongly influenced by surface effects to be a useful probe of bulk electronic structure. Going to hard X-ray photon energies and thus larger electron inelastic mean-free paths should provide a more accurate picture of bulk electronic structure. We present experimental data for hard X-ray ARPES (HARPES) at energies of 3.2 and 6.0 keV. The systems discussed are W, as a model transition-metal system to illustrate basic principles, and GaAs, as a technologically-relevant material to illustrate the potential broad applicability of this new technique. We have investigated the effects of …

Lattice Opening upon Bulk Reductive Covalent Functionalization of Black Phosphorus

The chemical bulk reductive covalent functionalization of thin-layer black phosphorus (BP) using BP intercalation compounds has been developed. Through effective reductive activation, covalent functionalization of the charged BP by reaction with organic alkyl halides is achieved. Functionalization was extensively demonstrated by means of several spectroscopic techniques and DFT calculations; the products showed higher functionalization degrees than those obtained by neutral routes.

Fabrication of layered nanostructures by successive electron beam induced deposition with two precursors: protective capping of metallic iron structures

We report on the stepwise generation of layered nanostructures via electron beam induced deposition (EBID) using organometallic precursor molecules in ultra-high vacuum (UHV). In a first step a metallic iron line structure was produced using iron pentacarbonyl; in a second step this nanostructure was then locally capped with a 2-3 nm thin titanium oxide-containing film fabricated from titanium tetraisopropoxide. The chemical composition of the deposited layers was analyzed by spatially resolved Auger electron spectroscopy. With spatially resolved x-ray absorption spectroscopy at the Fe L₃ edge, it was demonstrated that the thin capping layer prevents the iron structure from oxidation upon e…