Spectro-Microscopy with aberration correction for relevant techniques
The instrument is an aberration corrected photo-emission electron microscope equipped with an imaging energy analyzer and installed at the high flux density beamline UE49 SMART. The SMART microscope is the first PEEM, showing successfully the simultaneous compensation for spherical and chromatic aberrations, enabling an outstanding lateral resolution of 2.6 nm (LEEM) and 18 nm (energy filtered XPEEM using W4f XPS peak) together with an increase in transmission by a factor of 6, demonstrated under experimental conditions at BESSY-II.Selected Applications:
- Phase transitions: (a) Real time study of the crystalline to vitreous transition in ultra-thin silica films; (b) transformation between various iron oxide thin film structures supported on transition metals.
- Surface reactions: (a) Real time study of the effects of confinement in the kinetics of the water formation reaction; (b) Real time investigations of metal nanoparticles under reaction conditions: synergistic effects of multicomponent systems in coupled catalysis.
- Two dimensional systems: (a) Structural and electronic properties of mixed silica-germania thin films. (b) Real time study of the intercalation of gases in the SiO2 BL/Ru(0001) model system, (c) Quasi in-situ studies of the segregation properties Ni/Cu model catalysts for the hydrogenation of CO2.
- Quasi in-situ studies of the morphological changes on active Cu surfaces under CO2 electroreduction conditions.
- Real time observation of epitaxial in situ growth of metallic, organic or oxide films and nanoparticles.
NEXAFS, XMLD, XMCD, Surface Diffraction, X-ray Microscopy, PEEM, XPD, XPS, UPS, ARPES
depends on experiment - please discuss with Instrument Scientist
|Energy range||100 - 1800 eV|
|Energy resolution||10000 at 200 eV|
|Flux||1011 - 1013 ph/s/300mA|
|Polarisation||variable (linear and circular)|
|Focus size (hor. x vert.)||h x v = 3,7 µm x 5 µm (10 µm x 5 µm on specimen surface)|
|Phone||+49 30 8062 13430|
|More details||UE49_PGM SMART|
|Temperature range||200 - 1800 K|
|Pressure range||10-10 - 5x 10-6 mbar|
|Detector||aberration corrected and energy-filtered XPEEM/LEEM system|
|Manipulators||special sample holder design|
|Sample holder compatibility||ELMITEC sample holder
8-13 mm diameter (round samples)
8 mm x 8 mm up to 10 mm x 10 mm (square/rectangular)
sample thickness: 0.5 mm - 3 mm
Also special sample holders are used:
a) adapter for “flag style sample plate holder”
b) sample holder with contacts for electric circuits on the sample surface
c) sample holder with PBN heater for NAP applications
|Additional equipment||• Quasi in situ NAP reaction cell: pmax= 5 mbar; T= RT-700°C. A special sample cartridge provided with a boralectric (PBN) heater guarantees clean conditions for heating at near ambient pressures.
• Compact UHV plasma source for reactive treatment of various samples: O2, H2, N2, etc. Operation mode: hybrid and atomic.
• Quasi in situ electrochemical cell: samples must be 10 mm x10 mm with 2-2.5 mm thickness to comply with the sample holder and electrochemical cell sealing.
• Various evaporator ports pointing to the sample position in the specimen chamber (for real time observation of film growth)
• Gas dosing system in the specimen chamber of the microscope
• Evaporator port with micro-balance in the preparation chamber
|Resolution LEEM||2.6 nm|
|Resolution XPEEM (XPS)||18 nm|
|Energy resolution (XPEEM)||180 meV|
|Base pressure||10-10 mbar|
|Operation pressure||up to 5x 10-6 mbar|
|Sample storage in UHV||6|
|Temperature measurement||W/Re thermocouple or pyrometer|
|No of ports pointing on sample||8 (4 for evaporators)|
Spectro-Microscopy with Aberration correction for many relevant Techniques
The instrument is an aberration corrected photo-emission electron microscope equipped with an imaging energy analyzer and installed at the high flux density beamline UE49 SMART. The SMART microscope is the first PEEM, showing successfully the simultaneous compensation for spherical and chromatic aberrations, enabling an outstanding lateral resolution of 2.6 nm (LEEM) and 18 nm (energy filtered XPEEM using W4f XPS peak) together with an increase in transmission by a factor of 6, demonstrated under experimental conditions at BESSY-II.
The multitude of operation modes – microscopy, spectroscopy and diffraction of photo-emitted and reflected electrons – and the variety of methods, e.g. photoemission electron microscopy (PEEM), energy-filtered XPEEM, NEXAFS-PEEM, LEEM, NEXAFS, XPS, UPS, XMCD, XMLD, photoelectron diffraction (PED), valence band structure mapping, and LEED, allow for a comprehensive characterization of inhomogeneous surfaces and thin films on nanometer scale with a surface sensitivity of only a few atomic layers. Examples are the local chemical composition of metal nano-particles and of structural domains in thin oxide films, the local molecular orientation of inhomogeneous organic films and local band structure measurements of ordered silica films.
Furthermore, the fast direct (i.e. non-scanning) imaging combined with the possibilities to deposit material on the specimen surface in measurement position, to cool or anneal the sample and to expose the surface to reactive gases during operation enable the in-situ and real time study of complex processes like e.g. film growth, alloying, chemical surface reaction, thermal desorption or phase transition on nanometer scale in video rate with chemical and structural contrast.
Photoelectron EM (PEEM), energy-filtered XPEEM, NEXAFS-PEEM, X-ray Microscopy, LEEM, Hg-PEEM
NEXAFS, XPS, UPS, Angular-resolved PES, XMCD, XMLD,
- Diffraction/angular distribution:
Surface Diffraction, Photoelectron Diffraction (PED), Valence band structure mapping, LEED