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

Cs-corrected protoype Cs-corrected Cs/Cc-corr. Rose, Haider, Urban FEI TITAN 80 – 300 (2006) (1998) Three generations of aberration corrected HRTEMs PICO (2011)

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

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

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

Aberration corrected electron optics Lens C S = 0 P Image plane  TU Darmstadt (H. Rose)  EMBL Heidelberg (M. Haider)  Forschungszentrum Jülich (K. Urban) Haider, Rose, Urban et al. Nature 392 , 768 (1998) Volkswagen Stiftung

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 1 dE   d C c c 2 E Biggest impact of Cc-correction expected for: • large energy spread dE (EFTEM) • low accelerating voltages (low E)

PICO resolution Sub-Ångstrøm resolution at 80 kV Resolution improvement to 0.8 Å due to C C -correction Few- layer hexagon al boron nitride viewed along c - axis Fourier transform of 0.5 nm Haider et al, Ultramicroscopy C C and C S correct 108 (2008) 167 L. Houben

PICO: atomic resolution at 50 kV Graphene:Pd 9.8 nm -1 1 Å Pd Au/C 9.37 nm -1 2.46 Å inverted positive phase contrast 2 nm Lothar Houben (ER-C) sample courtesy of U.Bangert, University of Manchester

Case study Catalytic Rh-Nanoparticles in Ionic Liquid on Graphene PICO, U = 80 kV J. Barthel (ER-C), M. Marquardt (Univ. Düsseldorf)

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 Simulated image 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 occupied 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 STEM EFTEM Electron energy loss spectrum

Energy Filtering TEM Spherical 3 d   0 0 5 . C s s Aberration Chromatic  1 E c   0 d C Aberration c 2 E 0  Diffraction Limit  0 . 6 d  d  Delocalisation  0 . 5 d del 3 4  E     2 2 2 2 d d d d d tot c s d del

Wide field of view: SrTiO3 <100>, hollow-cone EFTEM Ti L 23 pre-edge 1 pre-edge 2 post-edge Ti-L 23 map Sr-M map (pre-edge)

EFTEM Resolution & Cc-Correction Cs corrected Cs and Cc corrected Cc=1.4 mm Cc=10 μ m W=10 eV W=50 eV Cc optical limit optical limit Delocalisation Delocalisation Diffraction Diffraction Cs Cc Cs -> optical resolution better than delocalisation -> large windows possible As in Krivanek et al, J. Microsc. 180 (1995) 277 R. F. Egerton, J. Electr. Microsc. 48 (1999) 711.

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

• Energy conversion Energy Applications • Catalytic nanoparticles • Photovoltaic cells 28 Marc Heggen, ER-C

Energy conversion strategies PLB „Power -to-Storage “ SOEC „Power -to-Fuel “ SOFC „Fuel -to-Power “ 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- O 2 catalysts for water separation CdSe: used for charge separation H 2 CdS: larger bandgap, charge transfer properties H 2 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

Stability of CdSe/CdS NP surfaces at 80 kV Focal series C 1 = -15.6 nm ... 9.6 nm C 5 = +3.5 mm, C 3 = -10.6 μ m PICO: Structural stability is given at 80 kV -> possibility to record focal series for residual aberration correction

Surface coordination and termination Focal series reconstruction Cd S/Se - occurrence of twin boundaries - Cd termination is ligand-stabilized Cd S/Se 1.4 Å

EFTEM of CdSe/CdS Nanoparticles (PICO) y t i s n Characteristic e t n edge I EFTEM  E series  E EFTEM ESI series of CdS/CdSe nanoparticles 80 kV, 35 eV - 235 eV, slit size 20 eV, step 10 eV c Se M 45 a b Se M 45 HRTEM S L 23 , Se M 23 jump ratio 5 nm 5 nm zero loss filtered image Se M 45 , Se M 23 & S L 23 Se M edge jump ratio EFTEM map Lothar Houben in collaboration with M. Bar Sadan, S. Mangel, Ben Gurion University

21%

BMBF-project SINOVA 21% 60%

Design Concept 2.74 nm Vertical Transport 2.88 nm SiO x Si 2.64 nm 4.90 nm 5.16 nm 2.40 nm Si/SiO 2 -Superlattices: 4.95 nm Fabrication by RPECVD at 250 ° C and Rapid Thermal Annealing at 900 to 1100 ° C Sample: B. Spangenberg, H. Kurz, IHT, RWTH Aachen, TEM: A. Sologubenko, M. Beigmohamadi

Transport Concepts Vertical Transport Lateral Transport

PICO Vertical Transport d am d cryst d am Si/SiO 2 -Superlattices: Fabrication by RPECVD and d cryst Laser annealing Sample: B. Spangenberg, H. Kurz, IHT, RWTH Aachen, TEM: M. Beigmohamadi

PICO: Energy Filtering TEM Si-L edge, 3 window meth. Maryam Beigmohamadi, Jörg Jinschek

T HANK Y OU !