Activity Leader
Prof. Dr. Henny Zandbergen
Fac. Of Applied Sciences
Kavli Inst. Nat.
Lorentzweg 1
NL-2628 CJ DELFT
NEDERLAND
Phone + 31 152 782 266
Fax     + 31 152 786 730
E-mail: H.W.Zandbergen@tnw.tudelft.nl
Website: http://nchrem.tnw.tudelft.nl/
TA8

 

The NCHREM laboratory at the Technical University of Delft is specialized in different transmission electron microscopy techniques with focus on high resolution and in-situ experiments. The laboratory has a unique monochromated microscope, resulting in an improved energy resolution for the determination of the electronic structure. Specifications are 0.1 eV for a spot size of 1.5 nm and 0.5 eV for a spot size of 0.2 nm. The necessary hardware and software for image and spectra interpretation are available.
The laboratory offers access to the following transmission electron microscopes:

 

  • FEI Monochromated Tecnai
  • FEI CM30 UT-FEG
  • Dual beam Strata DB235

The choice of the Philips microscopes was partly due to their capabilities, and partly to the prospects of collaboration with the manufacturer in the general development and improvement of electron microscopes. The most important parameters of the microscopes are listed below.

 

The most important properties of the microscopes at the NCHREM (Delft). EDS=Energy Dispersive Spectroscopy; PEELS= Parallel Electron Energy Loss Spectroscopy. ** 0.2 nm at 200 meV, 2 nm at 50 meV.


 

 

CM30T (1989)

CM30UT-FEG (1997)

Monochromated Tecnai (2002)

main application

composition, microstructure determination

composition, atomic arrangement, high-resolution atomic imaging

composition, atomic arrangement, local atomic bonding, and electronic structure determination

maximal voltage

300

300

200

point resolution (nm)

0.23

0.17

0.19

tilt possibilities

±45˚

±28˚

±28˚

information limit  (nm)

0.20

0.10

0.10

EDS, detection of elements heavier than

boron

boron

boron

probe size for EDS

1.5

0.7

0.2

STEM probe size (nm)

1.0

-

0.20

EFTEM

-

-

yes

HAADF detector

-

-

yes

EELS resolution

800 meV*

800 meV*

50 meV**

energy filtered imaging

-

-

yes

probe size for EELS (nm)

-

-

0.2 nm**

slow scan CCD camera

-

1024x1024

4096x4096

video camera

Gatan

Gatan off-axis

1024x1024 GIF



 

Transmission Electron Microscope FEI Monochromated Tecnai 200STEM-FEG

 

 clip_imagedel.jpg  

 

General Information

 

Location:

Physics building (# 22), Lorentzweg 1, 2628 AL, Delft

Key words:

HAADF, STEM, HR-EELS, monochromator, Electron Energy Loss Spectroscopy, (Scanning) Transmission Electron Microscopy

Main application:

Materials nano structure analysis: composition, atomic arrangement, local atomic bonding, and electronic structure determination

 

Instrument specification

 

The most important properties of the transmission electron microscopes. EDS=Energy Dispersive Spectroscopy; PEELS= Parallel Electron Energy Loss Spectroscopy. ** 0.2 nm at 200 meV, 2 nm at 50 meV.

 

 


Dual beam strata DB 235


A new development of the group's expertise and instrumentation is use of a combined focused ion beam and scanning electron microscope (FIB/SEM). The instrument is being used for the preparation of TEM specimens. A key feature of this instrument, is the possibility to prepare TEM lamellas - with thicknesses below 80 nm - from the most interesting sites of many types of materials. Furthermore, the group uses the FIB/SEM to make cross sections of materials at specific sites. Visual (SEM), chemical (EDX) and crystallographic (EBSD) analysis of these cross sections bring to light many of the macroscopic properties of the investigated materials. Actual examples are indentations in multilayers, cracks in coatings, and pigment particles in art objects. Finally, the instrument is increasingly being employed for the fabrication of devices with very small components, i.e. feature sizes down to 20 nm. Examples are nano-contacts on superconducting thin layers, hole arrays in free-standing or supported thin metallic films, nano-cantilevers for atomic force microscopy. Recently we started an exploration of the combined use of FIB and TEM to write structures with feature sizes down to the atomic level. The work on the FIB/SEM is partially funded by FEI. All partners in the various collaborations benefit from the possibilities of the dual beam.

 

TEM specimen preparation facilities available at the Centre

 


Suitable specimens for high resolution electron microscopy can be obtained almost routinely both in plane view and in cross section, with the following equipment: - ion mills: a Baltec RES100, a Gatan dual ion mill (model 600), and two Gatan precision ion processing systems (PIPS, model 691). - a Dual Beam, FIB/SEM combination, FEI strata DB 235 (see above) - a Tenupol-3 (Struers) dual-jet electrochemical polishing device. - a cryo-ultramicrotome, which will be modified to allow cutting in a specially designed glove box, such that air sensitive materials can be prepared. - a plasmacleaner. - a specimen manipulation system, developed by the Centre, can be used for handling specimens under controlled atmosphere and for specimen treatments like heating and gas reactions. Specimens can be mounted on a special specimen holder for the electron microscope, and can be transported to the microscope without exposing it to air. The system is accessible for specimens from other laboratories with a vacuum suitcase.