Spectroscopy (draft)

  • What we do

    We perform in-situ and real-time chemical, electronic and optical characterization of materials under different conditions, e.g. to identify and map different phases.

  • What we do

    We perform in-situ and real-time chemical, electronic and optical characterization of materials under different conditions, e.g. to identify and map different phases.

Spectroscopy

The kinetic energy of electrons emitted from atomic core levels after x-ray photo absorption is characteristic of the respective element and its chemical state, giving rise to individual spectral lines which can be used, e.g., to distinguish different oxidation states with XPS. Combined chemical and structural information are contained in so-called LEEM-IV measurements, where, in a separate experimental setup, low-energy electron reflectivity is recorded as a function of the incident electron energy. Such chemical and structural surface phases can be identified with a lateral resolution of a few tens of micrometers.

Complementary, the vibrational and structural properties of samples can be investigated using Raman and circular dichroism spectroscopy setups.

What kind of result do I get?

With XPS and LEEM both the chemical composition as well as the local structure and morphology of samples can be addressed. Since both techniques employ electrons with rather low energy, the information depth is restricted to a few atomic layers, and a decent electrical conductivity of the samples is required as well as ultra-high vacuum compatibility. Spectra and images can also be taken at elevated temperatures as well as during gas dosing (up to 10-4 mbar) to study changes of the chemistry, structure, and morphology during annealing or interaction with gases.

The local bonding geometry can be revealed with vibrational (Raman) spectroscopy. Circular dichroism spectroscopy (CDS) allows for the investigation of chiral structures, e.g. biomolecules adsorbed at interfaces. Both methods, Raman and CDS, are less surface sensitive than the electron-based methods of XPS and LEEM, and can be obtained from a wider class of specimens (e.g. insulators, non-UHV compatible materials.)

Principal Investigator

Prof. Dr. Jens Falta

Instrument Manager

Dr. Guilherme Dalla Lana Semione
University of Bremen
MAPEX Core Facility for Materials Analytics
TAB Building, Room 3.34
Am Fallturm 1, D-28359 Bremen
E-Mail: Instrument manager

Our key instruments

XPS chamber

Omicron DAR 400 + EA 125
X-ray photoemission spectrometer

  • Twin Al/Mg anode, 125 mm hemispherical analyzer, 7-channel parallel detection unit
  • UHV system additionally equipped with low-energy electron diffraction (LEED), scanning tunneling microscope (STM), and evaporation ports
LEEM chamber

SPE-LEEM Elmitec
Spectroscopic low-energy electron microscope

  • Full-field electron microscope with lateral resolution down to 10 nm; diffraction mode for micro-LEED images from selected areas with down to 250 nm in diameter
  • Hemispherical energy analyzer
  • Video rate imaging for real-time investigations, e.g., during material deposition or gas dosing; 100-1800 K temperature range
Raman spectroscope

Horiba LabRAM Aramis
Raman Spectrometer

  • 532 nm, 633 nm and 785 nm lasers
  • Measurements possible between 78 K and 1773 K
cd spectrometer

Applied Photophysics Chirascan
Circular dichroism spectrometer

  • Surface and interface characterization
  • (Secondary) structure detection of biomolecules

More available instruments

Current instrumentation belonging to MAPEX-CF can be found in the Instrument Database of the MAPEX Center for Materials and Processes.

A click on the logo will lead you to the database.
Atomic vs. sub-atomic layer deposition: impact of growth rate on the optical and structural properties of MoS2 and WS2 article picture
Spectroscopy| Electron Microscopy|

Atomic vs. sub-atomic layer deposition: impact of growth rate on the optical and structural properties of MoS₂ and WS₂

Christian Tessarek, Tim Grieb, Florian F Krause, Christian Petersen,  Alexander Karg, Alexander Hinz, Niels Osterloh, Christian Habben, Stephan Figge, Jon-Olaf Krisponeit, Thomas Schmidt,  Jens FaltaAndreas RosenauerMartin Eickhoff

2D Materials 11(2) (2024): 025031

DOI: 10.1088/2053-1583/ad313…


Growth, catalysis, and faceting of α-Ga2O3 and α-(InxGa1−x)2O3 on m-plane α-Al2O3 by molecular beam epitaxy pic
X-Ray Diffraction| Spectroscopy| Surface Analytics| Electron Microscopy|

Growth, catalysis, and faceting of α-Ga₂O₃ and α-(InₓGa₁₋ₓ)₂O₃ on m-plane α-Al₂O₃ by molecular beam epitaxy

Martin S. Williams, Manuel Alonso-Orts, Marco Schowalter, Alexander Karg, Sushma Raghuvansy, Jon P. McCandless, Debdeep Jena, Andreas RosenauerMartin Eickhoff, Patrick Vogt 

APL Materials 12 (2024): 011120

https://doi.org/10.1063/5.0180041

The growth of α-Ga2O3 and α-(InxGa1−x)2O3 on m-plane…


Figure from the paper of Guo et al.
3D Materials Analytics| Spectroscopy|

Gold Nanoparticle-Coated Bioceramics for Plasmonically Enhanced Molecule Detection via Surface-Enhanced Raman Scattering

Tongwei Guo, Jonas Schmidt, Mohammad Mangir MurshedKurosch RezwanMichael Maas

Advanced Engineering Materials 25 (2023): 2300942

https://doi.org/10.1002/adem.202300942

Herein, feasibility of plasmonically enhanced molecule detection via surface-enhanced Raman scattering for ceramics that are…


LEEM images
In-situ, real-time investigations| Spectroscopy|

Growth Mechanism of Single-Domain Monolayer MoS₂ Nanosheets on Au(111) Revealed by In Situ Microscopy: Implications for Optoelectronics Applications

Moritz Ewert, Lars Buß, Jeppe V. Lauritsen, Jens Falta, and Jan Ingo Flege

ACS Appl. Nano Mater. 5 (2022): 17702–17710

https://doi.org/10.1021/acsanm.2c03584

The nucleation and growth of single-layer molybdenum disulfide single-domain nanosheets is investigated by in situ low-energy electron…


LEEM
In-situ, real-time investigations| Spectroscopy|

Phase Separation within Vanadium Oxide Islands under Reaction Conditions: Methanol Oxidation at Vanadium Oxide Films on Rh(111)

Bernhard von Boehn, Anton Weißbach, Jon-Olaf Krisponeit, Jan Ingo Flege, Jens Falta, Luca Gregoratti, Matteo Amati, Patrick Zeller, and Ronald Imbihl

J. Phys. Chem. C. 126 (2022): 19101–19112

https://doi.org/10.1021/acs.jpcc.2c04174

Submonolayer coverages of V-oxide on Rh(111) condense during…


Picture
Spectroscopy|

Plasmonic porous ceramics based on zirconia-toughened alumina functionalized with silver nanoparticles for surface-enhanced Raman scattering

Tongwei Guoa, Md Nurul Karim, Kowsik Ghosh, M. Mangir Murshed, Kurosch Rezwan, Michael Maas

Open Ceramics 9 (2022): 100228

https://doi.org/10.1016/j.oceram.2022.100228

We demonstrate the feasibility of plasmonic porous ceramics which combine the optical properties of plasmonic nanoparticles with…


Picture
Spectroscopy|

Structural, vibrational, thermal, and magnetic properties of mullite-type NdMnTiO₅ ceramic

Kowsik Ghosh, M. Mangir Murshed, Thomas Frederichs, Naveen K. C. Muniraju, Thorsten M. Gesing

Journal of the American Ceramic Society 105 (2021): 2702-2712

https://doi.org/10.1111/jace.18261

Mullite-type RMn2O5 (R = Y, rare-earth element) ceramics are of ongoing research attention because of…


Thermal anomalies and phase transitions in Pb2Sc2Si2O9 and Pb2In2Si2O9 pic
X-Ray Diffraction| Spectroscopy|

Thermal anomalies and phase transitions in Pb₂Sc₂Si₂O₉ and Pb₂In₂Si₂O₉

Mathias Gogolin, M. Mangir Murshed, Lkhamsuren Bayarjargal, Detlef Klimm, Thorsten M. Gesing

Zeitschrift für Kristallographie - Crystalline Materials 236 (2021): 283-292

https://doi.org/10.1515/zkri-2021-2046

Pb2Sc2Si2O9 and Pb2In2Si2O9, respectively, the scandium and indium containing structural…


Picture
In-situ, real-time investigations| Spectroscopy|

Structural Transitions Driving Interface Pulses in Methanol Oxidation on Rh(110) and VOₓ/Rh(110): A LEEM Study

Bernhard von Boehn, Jon-Olaf Krisponeit, Jens Falta, Ronald Imbihl

Journal of Physical Chemistry C 125 (2021): 22539–22546

https://doi.org/10.1021/acs.jpcc.1c06106

With LEEM (low-energy electron microscopy) and micro-LEED as in situ techniques we have studied the structural transitions in the…


The Transition From MoS2 Single-Layer to Bilayer Growth on the Au(111) Surface pic
Spectroscopy|

The Transition From MoS₂ Single-Layer to Bilayer Growth on the Au(111) Surface

Moritz Ewert, Lars Buß, Nicolas Braud, Asish K. Kundu, Polina M. Sheverdyaeva, Paolo Moras, Francesca Genuzio, Tevfik Onur Menteş, Andrea Locatelli, Jens Falta, Jan Ingo Flege

Front. Phys(2021): 654845

https://doi.org/10.3389/fphy.2021.654845

The transition from single-layer to bilayer growth…


Eine kreisrunde Fläche aufgefächert
Spectroscopy|

The morphology of VO₂/TiO₂(001): terraces, facets, and cracks

Jon-Olaf Krisponeit, Simon Fischer, Sven Esser, Vasily Moshnyaga, Thomas Schmidt, Louis F. J. Piper, Jan Ingo Flege, Jens Falta

Nature Scientific Reports 10 (2020): 22374

https://doi.org/10.1038/s41598-020-78584-9

Vanadium dioxide (VO2) features a pronounced, thermally-driven metal-to-insulator…


Picture
X-Ray Diffraction| Spectroscopy|

KLi₂RE(BO₃)₂ (RE = Dy, Ho, Er, Tm, Yb, and Y): Structural, Spectroscopic, And Thermogravimetric Studies on a Series of Mixed-Alkali Rare-Earth Orthoborates

Pengyun Chen, M. Mangir Murshed, Michael Fischer, Thomas Frederichs, Thorsten M. Gesing

Inorg. Chem 59 (2020): 18214–18224

https://doi.org/10.1021/acs.inorgchem.0c02684

We report a detailed structural, spectroscopic, and thermogravimetric investigation of a new series of mixed-alkali rare-earth…


Adsorption of sulfur on Si(111) pic
Spectroscopy|

Adsorption of sulfur on Si(111)

Th. Schmidt, L. Buß, M. Ewert, G. Schönhoff, T. Wehling. J. Falta

Surface Science 694 (2020): 121561

https://doi.org/10.1016/j.susc.2019.121561

The adsorption of S on Si(111)- 7  ×  7 has been investigated for different preparation schemes and parameters. S was supplied from an electrochemical Ag…


Controlling the Multiscale Structure of Nanofibrous Fibrinogen Scaffolds for Wound Healing pic
Spectroscopy|

Controlling the Multiscale Structure of Nanofibrous Fibrinogen Scaffolds for Wound Healing

Karsten Stapelfeldt, Stephani Stamboroski, Irina Walter, Naiana Suter, Thomas Kowalik, Monika Michaelis and Dorothea Brüggemann

Nano Letters (2019) 19, 6554–6563

https://doi.org/10.1021/acs.nanolett.9b02798

As a key player in blood coagulation and tissue repair, fibrinogen has gained increasing…


LEEm picture
Spectroscopy|

Growth and structure of ultrathin praseodymium oxide layers on ruthenium (0001)

Jan Höcker, Jon-Olaf Krisponeit, Julian Cambeis, Alexei Zakharov, Yuran Niu, Gang Wei, Lucio Colombi Ciacchi, Jens Falta, Andreas Schaefer and Jan Ingo Flege 

Physical Chemistry Chemical Physics (2017) 19, 3480-3485

https://doi.org/10.1039/C6CP06853G

The growth, morphology, structure, and…


xps spectra
Spectroscopy|

Isotropic thin PTCDA films on GaN(0001)

C. Ahrens, J. I. Flege, C. Jaye, D. A. Fischer, T. Schmidt and J. Falta

Journal of Physics: Condensed Matter (2016) 28, 475003

https://doi.org/10.1088/0953-8984/28/47/475003

The growth of 3, 4, 9, 10-perylene tetracarboxylic dianhydride (PTCDA) on the Ga-polar GaN(0 0 0 1) surface has been…


Aktualisiert von: MAPEX-CF