From nano to PICO: the next generation of aberration corrected TEMs - - PowerPoint PPT Presentation

From nano to PICO:

the next generation of aberration corrected TEMs

Joachim Mayer

RWTH Aachen University and Forschungszentrum Jülich

2.46 Å

Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons

FEI TITAN 80 – 300 (2006)

PICO (2011)

Cs-corrected protoype Cs-corrected Cs/Cc-corr.

Rose, Haider, Urban (1998)

Three generations of aberration corrected HRTEMs

m mm nm µm Å Hair Light Transistor Atom Comparison of Resolution Limits of Optical Instruments pm Electron wavelength x 100 x 100

Spherical Aberration

Magnetic Lens Gaussian Image Plane Phase-Shift 500 correctors for spherical aberration installed worldwide

Chromatic Aberration two correctors for chromatic aberration (HRTEM) installed worldwide

Outline

• PICO and the correction of chromatic

aberration

• Low voltage HRTEM
• Applications to nanoparticles
• Atomic resolution EFTEM

2.46 Å

Lens

Image plane

Aberration corrected electron optics

• TU Darmstadt (H. Rose)
• EMBL Heidelberg (M. Haider)
• Forschungszentrum Jülich (K. Urban)

Volkswagen Stiftung

Haider, Rose, Urban et al. Nature 392, 768 (1998)

P

CS = 0

Chromatic Aberration

Correction Principle: Wien Filter E B image plane

Harald Rose and Max Haider

Correction Principle: Crossed Electrostatic/Magnetic Quadrupoles

Harald Rose and Max Haider

CCOR in Heidelberg, CEOS

828 mm, 470 kg, 160 channels

Chromatic Aberration

 E dE C d

c c

2 1 

Biggest impact of Cc-correction expected for:

• large energy spread dE (EFTEM)
• low accelerating voltages (low E)

PICO resolution

Fourier transform of CC and CS correct

Sub-Ångstrøm resolution at 80 kV Resolution improvement to 0.8 Å due to CC-correction

0.5 nm

• L. Houben

Few- layer hexagon al boron nitride viewed along c- axis Haider et al, Ultramicroscopy 108 (2008) 167

PICO: atomic resolution at 50 kV

Graphene:Pd

inverted positive phase contrast

2 nm

2.46 Å

Pd

9.37 nm-1

sample courtesy of U.Bangert, University of Manchester

9.8 nm-1 Au/C

1 Å

Lothar Houben (ER-C)

Catalytic Rh-Nanoparticles in Ionic Liquid on Graphene

• J. Barthel (ER-C), M. Marquardt (Univ. Düsseldorf)

Case study

PICO, U = 80 kV

Determination of the 3D shape of a nanoscale crystal with atomic resolution from a single image

• C. L. Jia, S. B. Mi, J. Barthel, D.W.Wang, R. E. Dunin-Borkowski, K.W. Urban and A.

Thust, NATURE MATERIALS | VOL 13 | NOVEMBER 2014

Experimental image Simulated image

Determined 3D atomic arrangement and displacements of atoms: atomically resolved view of the best-fitting 3D atomic arrangement for the sample region shown. Red spheres: fully

• ccupied Mg sites and blue spheres: fully occupied O sites. Increased colour saturation is used

to highlight surface atoms. In the surface layers, brown spheres indicate formally half-occupied Mg sites, while cyan spheres indicate formally half-occupied O sites.

Energy Filtering TEM vs. STEM-EELS EFTEM

STEM

Electron energy loss spectrum

Energy Filtering TEM

3

5 

s s

C . d 

  2 1 E E C d

c c 

  6 . 

d

d

4 3

5 .

E del

d   

Spherical Aberration Chromatic Aberration Diffraction Limit Delocalisation

2 del 2 d 2 s 2 c tot

d d d d d    

Wide field of view: SrTiO3 <100>, hollow-cone EFTEM Ti L23

pre-edge 1 pre-edge 2 post-edge Ti-L23 map Sr-M map (pre-edge)

EFTEM Resolution & Cc-Correction

• > optical resolution better than delocalisation
• > large windows possible

Delocalisation Cs Cc Diffraction

• ptical

limit

• ptical

limit Delocalisation Cs Cc Diffraction

Cc=1.4 mm Cc=10 μm W=50 eV W=10 eV

Cs corrected Cs and Cc corrected

As in Krivanek et al, J. Microsc. 180 (1995) 277

• R. F. Egerton, J. Electr. Microsc. 48 (1999) 711.

High Resolution EFTEM of Si

Pre edge 1 Pre edge 2 Si-L Map Post edge EFTEM, Si-L edge at 99 eV, energy window 40 eV 1.35 Å

Marc Heggen, ER-C

28

Energy Applications

• Energy conversion
• Catalytic nanoparticles
• Photovoltaic cells

SOFC

„Fuel-to-Power“

SOEC

„Power-to-Fuel“

PLB

„Power-to-Storage“

Energy conversion strategies

PLB = post lithium batteries SOEC = solid oxide electrolyser cells SOFC = solid oxide fuel cells

Power to Fuel: Hydrogen Production

CdSe/CdS hybride particles: use as photo- catalysts for water separation CdSe: used for charge separation CdS: larger bandgap, charge transfer properties How do growth, surface and interface/defects depend on the choice of organic ligands?

Lothar Houben, Juri Barthel (ER-C) collaboration with M. Bar Sadan, S. Mangel, Ben Gurion University

H2 H2 O2

Stability of CdSe/CdS NP surfaces at 80 kV

PICO: Structural stability is given at 80 kV

• > possibility to record

focal series for residual aberration correction Focal series C1 = -15.6 nm ... 9.6 nm C5 = +3.5 mm, C3 = -10.6 μm

Surface coordination and termination

Cd S/Se Cd S/Se

1.4 Å

• occurrence of twin boundaries
• Cd termination is ligand-stabilized

Focal series reconstruction

EFTEM of CdSe/CdS Nanoparticles (PICO)

HRTEM

a

zero loss filtered image

Se M45 jump ratio

Se M45

S L23, Se M23

b c

5 nm 5 nm

Se M edge jump ratio Se M45, Se M23 & S L23 EFTEM map

Lothar Houben in collaboration with M. Bar Sadan, S. Mangel, Ben Gurion University

E

I n t e n s i t y E

Characteristic edge EFTEM series

EFTEM ESI series of CdS/CdSe nanoparticles 80 kV, 35 eV - 235 eV, slit size 20 eV, step 10 eV

21%

21% 60%

BMBF-project

SINOVA

Design Concept Vertical Transport

Si/SiO2-Superlattices: Fabrication by RPECVD at 250°C and Rapid Thermal Annealing at 900 to 1100°C

2.40 nm 2.64 nm 2.88 nm 2.74 nm

SiOx Si

4.95 nm 5.16 nm 4.90 nm

Sample: B. Spangenberg, H. Kurz, IHT, RWTH Aachen, TEM: A. Sologubenko, M. Beigmohamadi

Transport Concepts

Vertical Transport Lateral Transport

PICO Vertical Transport

Si/SiO2-Superlattices: Fabrication by RPECVD and Laser annealing

Sample: B. Spangenberg, H. Kurz, IHT, RWTH Aachen, TEM: M. Beigmohamadi

dam dam dcryst dcryst

PICO: Energy Filtering TEM Si-L edge, 3 window meth.

Maryam Beigmohamadi, Jörg Jinschek

THANK YOU!