Electron Microscopy

  • Momentum resolved STEM

    What we do

    We investigate our samples using high-energy electron beams to obtain images with resolution down to the atom scale. We focus on the development of quantitative methods for electron microscopy.

  • comparison of different inputs

    What we do

    We investigate our samples using high-energy electron beams to obtain images with resolution down to the atom scale. We focus on the development of quantitative methods for electron microscopy.

  • beam electron diffraction patterns

    What we do

    We investigate our samples using high-energy electron beams to obtain images with resolution down to the atom scale. We focus on the development of quantitative methods for electron microscopy.

  • Electrical Polarization

    What we do

    We investigate our samples using high-energy electron beams to obtain images with resolution down to the atom scale. We focus on the development of quantitative methods for electron microscopy.

Electron Microscopy

We use transmission electron microscopy (TEM) to investigate the atomic structure and composition of nanomaterials. In the high-resolution TEM (HRTEM) mode the whole region of interest of our specimen is illuminated with the electron beam and the image is formed with the objective lens and further magnifying lenses. In the Scanning TEM (STEM) mode, the electron beam is focused to a diameter down to 50 pm. The focused beam is scanned over the specimen and scattered electrons are detected with different detectors. Images are formed by plotting the detector signal at each scan position.  The composition of the specimen is measured with energy dispersive X-ray analysis (EDX) and energy loss spectroscopy (EELS). Electron tomography yields the 3D structure of our specimen.

What kind of result do I get?

The high-resolution TEM and STEM images show the atomic structure of the specimen projected along the electron beam direction. The images reveal the crystal structure, dislocations and stacking faults. The positions of atom columns are measured with an accuracy of a few picometers. Distances between atom columns give information on the strain distribution in our specimen. In the STEM mode, using the high-angle annular dark field (HAADF) detector, the brightness of an atom column increases with the atomic number, so that we can distinguish different elements in the images. An atom hit by the electron beam emits a characteristic X-ray spectrum. Its measurement in STEM allows 2D elemental mapping, detecting elements even at small concentrations below 1%.

Area responsible

Prof. Dr. rer-nat. Andreas Rosenauer

Service Electron Microscopy

Application Scientist

Dr. Marco Schowalter


MAPEX Center for Materials and Processes
University of Bremen

Otto-Hahn Allee 1, D-28359 Bremen
Phone: +49 421 218 62263
Email: schowalter@ifp.uni-bremen.de


Dr. Thorsten Mehrtens


MAPEX Center for Materials and Processes
University of Bremen

Otto-Hahn Allee 1, D-28359 Bremen
Phone: +49 421 218 62273
Email: mehrtensprotect me ?!ifp.uni-bremenprotect me ?!.de

Our key instruments

FEI Titan picture

FEI TITAN 80/300
Image corrected (scanning) transmission electron microscope

  • resolution 80 pm in TEM and 130 pm in STEM
  • EDX, EELS, Möllenstedt-Dücker biprism
  • Tomography holder
more
Thermo Fischer picture

Thermo Fisher  SPECTRA 30/300
Probe corrected (scanning) transmission electron microscope

  • STEM resolution 50 pm
  • X-FEG, Monochromator
  • Electron Microscope Pixelated Array Detector (EMPAD)
    (direct electron detector with 1000 frames per second)
  • Super-X EDS detector
  • On-axis 360° rotation tomography holder
  • dual-axis tomography holder
more
electron scanning microscope

FEI Nova 200 NanoLab
Scanning electron microsope with focused Ga-ion Beam

  • Preparation of TEM samples
  • SEM resolution 1-2 nm
  • acceleration voltage 2 kV – 30 kV
  • probe current 2.5 pA – 37 nA
  • Platinum metal deposition

More available instruments

More information about the instrumentation available at MAPEX and 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.

Research Highlights

3D Materials Analytics| Spectroscopy|

Growth and characterization of sputter-deposited Ga2O3-based memristive devices

Aman Baunthiyal; Jon-Olaf KrisponeitMarco SchowalterThorsten Mehrtens; Alexander Karg; Andreas RosenauerMartin Eickhoff; Jens Falta

Applied Physics Letters (2023), 123, 213504

https://doi.org/10.1063/5.0170354

In the last few years, there has been significant interest in gallium oxide…


Figure from the publication
Spectroscopy| Electron Microscopy|

Correlative analysis on InGaN/GaN nanowires: structural and optical properties of self-assembled short-period superlattices

Manuel Alonso‑Orts, Rudolfo Hötzel, Tim Grieb, Matthias Auf der Maur, Maximilian Ries, Felix Nippert, Benjamin März, Knut Müller‑Caspary, Markus R. Wagner, Andreas Rosenauer, Martin Eickhoff

DiscoverNano 27 (2023)

https://doi.org/10.1186/s11671-023-03808-6

The influence of self-assembled…


TEM
Materials Modelling| Electron Microscopy|

Deformed Honeycomb Lattices of InGaAs Nanowires Grown on Silicon-on-Insulator for Photonic Crystal Surface-Emitting Lasers

Cristian Messina, Yongkang Gong, Oumaima Abouzaid, Bogdan-Petrin Ratiu, Tim Grieb, Zhao Yan, Andreas Rosenauer, Sang Soon Oh, Qiang Li

Adv. Optical Mater. 2022, 2201809

https://doi.org/10.1002/adom.202201809

Photonic crystals can be used to achieve high-performance surface-emitting lasers and…


Updated by: MAPEX