Advanced Imaging and Analysis at
NanoscaleJapan-Canada Joint Seminar on Advanced Electron
Microscopy and its application-2nd Canada-Japan Microscopy Societies Symposium 2021November 15 - 17, 2021 (Canada)
11 月, 16 -18 日, 2021 年 (日本)
Virtual Event
Click Here to Join Meeting
Zoom Meeting ID: 813 7163 6230

Click Here to Join Meeting
ClickPasscode:
Here to 085804
Join Meeting

1|PageOrganizers
Canada (カナダ):
Marek Malac (NRC-NANO and Dept. of Physics, University of Alberta), Misa Hayashida(NRC-NANO), Alan Maigne (Stewart Blusson Quantum Matter Institute, University of British
Columbia)
日本 (Japan):
森 茂生 Mori Shigeo (Osaka Prefecture University), 原田 研 Harada Ken (RIKEN)

2|PageSponsors

Half part of this symposium managed in Japan was supported by JSPS-bilateral program.
(JPJSBP220209905)

The goal of the workshop is to identify joint scientific interests and to promote scientificcollaborations among MSC and JSM members. This year, the aim is to expand awareness of JSM
and MSC members on the development of advanced electron and ion microscopy tools, methods
and applications. New developments in instrumentation, improved understanding of fundamental
limits of electron and ion microscopy and new tools and methods in data processing and theirapplications are welcome.

3|PageMessage from Microscopical Society of Canada president,
Prof. Kathryn Grandfield
Dear colleagues,
On behalf of the Microscopical Society of Canada (MSC), it is my honour to welcome you to thesecond annual Japan Microscopy Society (JSM) and MSC Symposium. This year’s theme on
Advanced Imaging and Analysis at the Nanoscale marks an exciting exchange between oursocieties sure to enhance our collaborations and pursuit of new research methods in microscopy. I
congratulate the organizers on assembling such an exciting scientific panel and virtual meeting. I
wish all attendees an inspiring and successful conference. We hope to meet in person next year!
Kathryn Grandfield
President, Microscopical Society of Canada

4|PageMessage from Japanese Society of Microscopy president,
Yuichi Ikuhara 先生

Last year, the Japanese Society of Microscopy (JSM) planned JSM and the Microscopy Society ofCanada (MSC) joint symposium on “Advanced Electron Microscopy and Its Application”. Thissymposium was initially organized by two countries collaboration program supported by JSPS
(Japan Society for the Promotion of Science). But, unfortunately, we were forced to cancel this
symposium due to the global spread of coronavirus infections (COVID-19). However, several
voluntary members from JSM and MSC have continued to find a chance to organize JSM-MSC
symposium to further enhance the international exchange and mutual collaboration between two
countries as soon as possible. Finally, they have reached the conclusion to organize the virtual
symposium on “Advanced Imaging and Analysis at Nanoscale” as the second Canada -Japan
Microscopy Societies Symposium 2021. This symposium includes new developments in
instrumentation, improved understanding of fundamental limits of electron and ion microscopy,
new tools and methods in data processing and their applications, and also coincides with one of
JSM policies “Internationalization”. I hope this symposium will be successfully held to further
strengthen the relationships between the two countries.
Finally, I sincerely thank Prof. Shigeo Mori and Dr. Ken Harada from JSM and Prof. Marek
Malac, the former president of MSC, Dr. Misa Hayashida and Dr. Alan Maigné from MSC for
their big effort to organize this wonderful symposium.

Yuichi Ikuhara
President, Japanese Society of Microscopy

5|PageMessage from symposium organizers
As the announcement implies, this is the second joint symposium of the Japanese Society ofMicroscopy (JSM) and the Microscopy Society of Canada (MSC). This year, the topic is“Advanced Imaging and Analysis at Nanoscale”. We are grateful to have received excellent
scientific contributions from both the young generation as well as the pioneers of electron
microscopy. We are particularly pleased to have a special guest speaker, Prof. Sumio Iijima, of the
carbon nanotube fame.
Our long term goal is to help build scientist-to-scientist connections between JSM and MSC. A
joint annual symposium is but a small step towards researcher visits that could bring further
exciting science.
Covid-19 forced us to opt for a virtual rather than in-person meeting once again. (Although thecase can be made that the virtual world weather is more pleasant than November in Edmonton.)
Hopefully, the next JSM-MSC meeting will be held in person as early as 2022.
We are grateful for the sponsorship support of this year's symposium. It was kindly provided by
Hitachi High Tech Canada and by Soquelec Ltd., who represent JEOL in Canada. Extensive thanks
belongs to personnel who helped with practical aspects of the symposium. They are, Catherine
Vachon and Michelle Hiltz at NRC-NANO, 眞田春佳 (Sanada Haruka) at Osaka Prefecture
University and 嶌田惠子 (Shimada Keiko) at RIKEN.
Please stay tuned for the 3rd annual joint symposium that will be held in 2022.
The JSM-MSC organizing committee working for you in both Canada and Japan,
Marek Malac, Misa Hayashida, Alan Maigne, 森 茂生(Mori Shigeo), 原田 研 (Harada Ken)

6|PageSCHEDULE
Join Zoom Meeting: https://us02web.zoom.us/j/81371636230?pwd=RVRBNDZ3M2p2bm1HdzVEVVpjN3E1dz09
Meeting ID: 813 7163 6230
Passcode: 085804
東京 (Tokyo)
UTC (+9 hr)

CanadaEdmonton
UTC (-7hr)

CanadaEastern time
UTC (-5 hr)

November 15, 2021
(Monday in Edmonton)
16, 火曜日 東京
Chair: Alan Maigné, Ken Harada

November 16, 2021
(Tuesday in Edmonton)
17, 水曜日 東京
Chair: Shigeo Mori, Misa Hayashida

November 17, 2021
(Wednesday in Edmonton)
18, 木曜日東京
Chair: Alan Maigné, Shigeo Mori, Ken Harada

3:50 – 4:00 pm

5:50 – 6:00 pm

WelcomeWelcome7:50 – 8:00 am

4:00 – 4:20 pm

6:00 – 6:20 pm

Welcome & logistics
Ken Harada & Marek Malac
Plenary Session

Plenary Session

8:00 – 8:20 am

6:00 – 6:40 pm

Ray Egerton
What Determines the Spatial Resolution in
Microscopy?
Zoom photo of participants (3 minutes)

Arthur BlackburnApplication of 4D-STEM at 30 kV for structure analysis ofblock co-polymers and high-resolution multi-slice phaseretrieval
Koji Harano
Visual Molecular Science at Interface of Self-Assembly andElectron Microscopy

Plenary Session

Plenary Session

Sumio Iijima

Yuichi Ikuhara

4:00 – 4:20 pm

4:40 – 5:00 pm

6:40 – 7:00 pm

5:00 – 5:20 pm

7:00 – 7:20 pm

Atomic resolution STEM-EDS imaging of cations
ordering of Ti-Nb and Nb-W ternary oxides for
LIBs anodes

Atomic-Scale Dynamic Observations of Interface, Surface
and Grain Boundary Phenomena

5:20 – 5:40 pm

7:20 – 7:40 pm

5:40 – 6:00 pm

7:40 – 8:00 pm

Raynald Gauvin
EDS and EELS of Lithium Materials from 0.5 to 30
keV
Nadi Braidy
Progress on Multivariate Statistics to Improve
Spectrum Image Interpretation

Roghayeh Nikbakht
Contribution of microstructure in oblique impact morphology ofhigh entropy CrMnCoFeNi particles
Yoshifumi Oshima
Atomic bond stiffness in Pt atomic chains measured by TEM
coupled with a quartz LER

6:00 – 6:20 pm

8:00 – 8:20 pm

6:20 – 6:40 pm

8:20 – 8:40 pm

Kohei Aso
Data-Driven Electron Microscopy Reveals ShapeDependent Subpercent Strains in Gold Nanorods
Anitha Jose
Mapping electrostatic potential gradient in GaN NW
p-n junctions using electron holography.

Xuan Quy Tran
Thermal Evolution of Alloying State in Ternary IrPdRu
Nanoparticles
Alyssa Williams
Utilization of Correlative Light and Electron Microscopy for
Analyzing the Structural Organization of Bacterial
Microcrystalline Cellulose.

6:40 – 7:00 pm

8:40 – 9:00 pm

Takayuki Nakamuro
Capturing the moment of nucleation and tracing the
crystal growth by SMART-EM

7:00 – 7:20 pm

9:00 – 9:20 pm

Rodney Herring
Phase Imaging Electron Intensities on the Diffraction
Plane

Mohammadparsa Khakpour
Manual versus automatic analysis of microglial spatial
characteristics: a comparison in the hippocampus of healthy
adult mice
Ben Cardoen
Belief theory enables detection of Caveolae in superresolution
microscopy.

7:20 – 7:25 pm

9:20 – 9:25 pm

Maureen Lagos
Phonon spectroscopy and Imaging at the
Nanoscale

8:20 – 8:40 am

Jun Yamasaki
TEM/STEM Intensity Modulation with Increasing
Thickness Induced by Electron Multiple Scattering
Phenomena in Materials
Marek Malac
NanoMi: a Public-License Platform for Electron
Microscopy Development and Education

8:40 – 9:00 am

Junji Yamanaka
STEM-Moiré Applications to Crystalline Specimens
without using High-End Microscopes
Alan Maigné
Development of Electron Microscopy toward
Analysis of Optical and Quantum Effects in
Nanomaterials.
Hiroshi Okamoto
TEM at Millikelvin Temperatures: What Would It Be
Useful for?
Misa Hayashida
Higher-order structure of barley chromosomes
observed by Electron Tomography

9:20 – 9:40 am

Tomokazu Yamamoto
In-situ STEM observation of Ni catalyst during dry
methane reforming

10:40 – 11:00 am

Hesham El-Sherif
STEM and EELS of Spontaneous Incommensurate
van der Waals Heteroepitaxy
Closing remarks
Ken Harada, Misa Hayashida

11:00 – 11:20 am

Zoom/Conference hosts Catherine.Vachon@nrc-cnrc.gc.ca or Michelle.Hiltz@nrc-cnrc.gc.ca

9:00 – 9:20 am

9:40 – 10:00 am

10:00 – 10:20 am
10:20 – 10:40 am

11:20 – 11:25 am

BOOK OF ABSTRACTS-TABLE OF CONTENTS

Plenary Sessions
Day 1
Ray Egerton
What Determines the Spatial Resolution in
Microscopy?
Day 1
Sumio Iijima
Atomic resolution STEM-EDS imaging of
cations ordering of Ti-Nb and Nb-W ternaryoxides for LIBs anodes.
Day 2
Yuichi Ikuhara
Atomic-Scale Dynamic Observations ofInterface, Surface and Grain Boundary
Phenomena.
Day 3
Maureen Lagos
Phonon spectroscopy and Imaging at the
Nanoscale.

Page 12Page 13

Page 14

Page 15

Day 1 Abstracts

Raynald Gauvin
EDS and EELS of Lithium Materials from 0.5
to 30 keV.
Nadi Braidy
Progress on Multivariate Statistics to Improve
Spectrum Image Interpretation.
Kohei Aso
Data-Driven Electron Microscopy Reveals
Shape-Dependent Subpercent Strains in Gold
Nanorods.
Anitha Jose
Mapping electrostatic potential gradient in
GaN NW p-n junctions using electron
holography.
Takayuki Nakamuro
Capturing the moment of nucleation andtracing the crystal growth by SMART-EM.
Rodney Herring
Phase Imaging Electron Intensities on the
Diffraction Plane.

Page 16

Page 17

Page 18

Page 19

Page 20

Page 21

Day 2 Abstracts
Arthur BlackburnApplication of 4D-STEM at 30 kV for
structure analysis of block co-polymers andhigh-resolution multi-slice phase retrieval.
Koji Harano
Visual Molecular Science at Interface of SelfAssembly and Electron Microscopy.
Roghayeh Nikbakht
Contribution of microstructure in obliqueimpact morphology of high entropy
CrMnCoFeNi particles.
Yoshifumi Oshima
Atomic bond stiffness in Pt atomic chainsmeasured by TEM coupled with a quartz
LER.
Xuan Quy Tran
Thermal Evolution of Alloying State in
Ternary IrPdRu Nanoparticles.
Alyssa Williams
Utilization of Correlative Light and Electron
Microscopy for Analyzing the Structural
Organization of Bacterial Microcrystalline
Cellulose.
Mohammadparsa Khakpour
Manual versus automatic analysis of
microglial spatial characteristics: acomparison in the hippocampus of healthy
adult mice.
Ben Cardoen
Belief theory enables detection of Caveolae insuperresolution microscopy.

Page 22

Page 23

Page 24

Page 25

Page 26

Page 27

Page 28

Page 29

Day 3 Abstracts
Jun Yamasaki
TEM/STEM Intensity Modulation with
Increasing Thickness Induced by Electron
Multiple Scattering Phenomena in Materials.
Marek Malac
NanoMi: a Public-License Platform forElectron Microscopy Development and
Education.
Junji Yamanaka
STEM-Moiré Applications to Crystalline
Specimens without using High-End
Microscopes.
Alan Maigné
Development of Electron Microscopy toward
Analysis of Optical and Quantum Effects in
Nanomaterials.
Hiroshi Okamoto
TEM at Millikelvin Temperatures: What
Would It Be Useful for?
Misa Hayashida
Higher-order structure of barley
chromosomes observed by Electron
Tomography.
Tomokazu Yamamoto
In-situ STEM observation of Ni catalyst
during dry methane reforming.
Hesham El-Sherif
STEM and EELS of Spontaneous
Incommensurate van der Waals
Heteroepitaxy.

Page 30

Page 31

Page 32

Page 33

Page 34

Page 35

Page 36

Page 37

What Determines the Spatial Resolution in Microscopy?
Ray Egerton*1

Physics Department, University of Alberta, Edmonton, AB T1W 2E2, Canada.
regerton@ualberta.ca*

As usual, the answer depends on how you phrase the question, but we can identify the following
factors as being of particular importance for electron microscopes.
Lens optics, including the presence of apertures and/or aberration correctors.
Microscope environment, including vibrations, pressure and temperature changes.
Power-supply stability, readout speed.
Beam spreading, important in STEM and EDX imaging.
Coulomb delocalization, sometimes important for EELS studies.
Electron statistics and radiation damage, critical for some specimens.
These questions will be addressed in turn but the main purpose of the talk will be to advocate the use ofa point-spread function (PSF) for specifying resolution [1], and dose-limited resolution (DLR) in thecase of beam-sensitive specimens [2]. Some examples are shown below.
References:[1] R F Egerton, Ultramicroscopy, Vol.145, (2014), pages 85-93.
[2] R F Egerton, Micron, Vol.119, (2019), pages 72-87.

Fig. 1 PSF for beam spreading (solid blue curve) Fig. 2. PSF for Coulomb delocalization of 100keV
calculated for 100keV electrons at the exit surface electrons (blue curve), calculated for an energy lossof a 100nm sample of amorphous silicon. The
of 25 eV and FWHM = 25/k0θE. The red dashedtails of this function arise from elastic scattering curve represents electron intensity per unit radiusand contribute 60% of the integrated intensity.
and the yellow curve is its cumulative sum.

12 | P a g e

Atomic resolution STEM-EDS imaging of cations ordering of Ti-Nb and Nb-W ternary oxides for
LIBs anodes
1*
2
Sumio Iijima , Zheng Liu , Ichiro Ohnishi3, Wenhui Yang4 ＆ Syo Matsumura4
1

Meijo University, Graduate School of Science and Technology, Nagoya 468-8502, Japan
Innovative Functional Materials Research Institute, National Institute of Advanced Industrial Scienceand Technology (AIST), Nagoya 463-8560, Japan
3
JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan
4
Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
819–0394, Japan*iijimas@meijo-u.ac.jp
2

Atomic resolution STEM-EDS imaging method is used to solve order–disorder problems incomplex metal oxide crystals, supplementing conventional X-ray or neutron diffraction. The materials
were ternary metal oxides Ti2Nb10O29 and 4Nb2O5・9WO3 (2Nb2O5・7WO3), which have recently
attracted attention as energy storage materials in lithium-ion batteries. The most of LIBs researchers
assumed these ternary oxides to be solid-solution and did not pay attention to cation chemical ordering.
Our study reveals the presence of obvious chemical ordering of metal ions in these materials and therelative occupancies of cations at each metal atom site were determined directly from the EDS images
taken by JEM-ARM300F operated at 300kV. Towards quantification of the atomic EDS images weinvestigated an effect of electron channeling at individual atomic columns.
1) Sumio Iijima, Ichiro Ohnishi, Wenhui Yang and Syo Matsumura, Comm. Mater., 2, 1-9 (2021).
2) Sumio Iijima, Ichiro Ohnishi and Zheng Liu, Scientific Reports, 11, 1-11 (2021).

Figure 1. (a) A STEM-ABF image of a Ti2Nb10O29 Fig. 2. Atomic resolution STEM-EDS image of acrystal in the [010] orientation, showing the metal crystal of 2Nb2O5・7WO3. (a) A schematic model
atomic columns and oxygen (faint dots). (b) Aof the crystal. (b) A STEM–EDS overlay image
STEM-EDS overlay crystal image recorded using recorded using the Nb Lα X-ray (green) and W Mα
the Ti Kα emission(green). Nb Lα(red) and O
X-ray (red) lines, which corresponds to the model
Kα(blue), showing a segregation of the metal
depicted in panel (a).
atomic columns in an ordered fashion.

13 | P a g e

Atomic-Scale Dynamic Observations of Interface, Surface and Grain Boundary Phenomena
Yuichi Ikuhara1, 2, 3*
1

2

Institute of Engineering Innovation, University of Tokyo, Tokyo 113-8656, Japan
Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan3
WPI Research Center, AIMR, Tohoku University, Sendai, 980-8577, Japan*ikuhara@sigma.t.u-tokyo.ac.jp

Materials properties depend on the dynamic behavior under various conditions such as temperature,stress, atmosphere. For example, mechanical properties of polycrystals are influenced by the interactionof grain boundary, dislocation and crack. On the other hand, functional properties are often influenced
by ion diffusion at service temperatures. So far, many atomic scale observations have been performed
for understanding fracture, deformation, diffusion and so on, but these experiments were mostly carriedout statically, and the dynamic behavior is still not well understood yet. In addition, these dynamic
behaviors often occur at interface and surface. In this study, the in-situ nanoindentation experiments
were conducted for SrTiO3 and Al2O3 bicrystals inside TEM to understand their deformation process at
the interfaces. For observing ion diffusion from the surface, single crystal of lithium ion battery (LIB)
were used for the ex-situ experiment as a model system.
For observing dislocation-interface interaction, various types of GBs including CSL (Coincidence
Site Lattice) GBs and low angle tilt and twist GBs for SrTiO3 and Al2O3 were systematically prepared.
Various interface phenomena such as dislocation pile-up at GBs, jog formation, jog-drag motion,
deformation twinning were dynamically observed by these experiments. The dislocation-GB interaction
and its dependence on the GB characters, the propagation mechanism of deformation twinning will be
discussed in detail. In addition, the crack propagation behavior of Zr-doped Al2O3 GB was directly
observed, and the as-fractured wall surfaces were characterized by Cs corrected STEM. It was found thatthe crack propagated in zigzag manner within the segregated Zr atom layers. The relationship of theatomic-scale crack propagation path and the grain boundary structure will be discussed in detail.
The properties of lithium ion battery (LIB) cathodes strongly depend on the dynamic diffusion oflithium ions during charge/discharge process. Then, direct visualization of lithium site is required tounderstand the mechanism of the diffusion of lithium ions. In this study, Cs corrected STEM were applied
to directly observe the {010} surface, which corresponded to perpendicular to the 1-D diffusion
orientation, of the olivine LixFePO4. Commercially available LiFePO4 singe crystals were used for all
experiments. The crystals were cut perpendicular to their <010> axis and polished, and the structures of{010} surfaces before and after chemical delithiation were characterized by STEM. It was found thatorientation of boundary layers at the FePO4/LiFePO4 interface gradually changed from lower index
planes to higher index planes. The dynamic diffusion mechanism of the lithiation/delithiation from andto the surface will be discussed based on the observation results.
References:[1] S. Kondo, T. Mitsuma, N. Shibata, Y. Ikuhara, Sci. Adv., 2[11], e1501926 (2016).
[2] S. Kondo, A. Ishihara, E. Tochigi, N. Shibata, and Y. Ikuhara, Nature Commun., 10, 2112 (2019).
[3] J.Wei, B.Feng, R.Ishikawa, T.Yokoi, K.Matsunaga, N.Shibata and Y.Ikuhara, Nat. Mater. , doi:
10.1038 / s41563-020-00879-z (2021).
[4] S. Kobayashi, C.A. J. Fisher,T.Kato, Y.Ukyo, T.Hirayama and Y.Ikuhara, Nano Lett.,16,5409 (2016)[5] S. Kobayashi, A. Kuwabara, C. A.J. Fisher, Y. Ukyo and Y. Ikuhara, Nat. Commun., 9, 2863 (2018)14 | P a g e

Phonon Spectroscopy and Imaging at the Nanoscale
Ka Y. Lee1, Zihan Lyu1, Elliot K. Beutler2, Ulrich Hohenester3, Philip E. Batson4, David J. Masiello2,
Maureen J. Lagos1,51Department of Materials Science and Engineering, McMaster University, Hamilton, Canada.
Department of Chemistry, University of Washington, Seattle, USA.
3
Department of Physics, University of Graz, Graz, Austria.
4
Department of Physics, Rutgers University, New Jersey, USA.
5
Canadian Centre for Electron Microscopy, McMaster University, Hamilton, Canada.
*
mjlagos@mcmaster.ca
2

The development of monochromators implemented in STEMs has opened the doors forphonon/vibrational spectroscopy studies in nanomaterials using atom-wide monochromatic electronprobes [1]. Instrumental developments are still in progress and energy resolutions of 3.7 meV at 60 kV
were recently obtained [2]. As it is usual the case, vibrational EELS experiments are complex and datainterpretation presents enormous challenges. But despite these barriers the EELS community has madesignificant progress in obtaining a much deeper understanding of the inelastic electron scattering byphonons in nanoscale systems. In this presentation, we will describe this progress by highlighting thefollowing results: (i) imaging surface and bulk phonon modes in a single nanoparticle [3], (ii) plasmonphonon coupling in infrared antennas [4], (iii) role of the substrate in the phonon response of
nanoparticles [5], and (iv) the development of a thermometry methodology to measure local
temperature in single nanostructures using energy-loss and energy-gain scattering [6]. Our results
provide progress in understanding the excitation of surface and bulk phonons sustained in nanoscale
volumes of matter using swift electrons.
References:[1] T. Miyata, et al, Microscopy 63, (2014), 377. / O. Krivanek, et al, Nature 514, (2014), 209.
[2] Private communication with Ondrej Krivanek and Tracy Lovejoy.
[3] M. J. Lagos, et al, Nature 543, (2017), 529. / M. J. Lagos, et al, Microscopy 67, (2018), i3.
[4] M. J. Lagos, et al, ACS Photonics 8, (2021) ,1293.
[5] E. K. Beutler, et al, Physical Review B 103, (2021), 165418.
[6] M. J. Lagos and P. E. Batson, NanoLetters 18, (2018), 4556.
[7] We acknowledge financial support of Canada NSERC.

15 | P a g e

EDS and EELS of Lithium Materials from 0.5 to 30 keV
Raynald Gauvin1*, Nicolas Brodusch1 and Frédéric Voisard1
McGill University, 3610 University, Montreal, Canada, H3A 0C5

1

This paper will present state of the art results acquired with the SU-9000 dedicated 30 keV (and less)
STEM that has EELS capabilities. It has a resolution of 0,22 nm in bright field STEM without
aberration correctors. It is equipped with an Extreme SDD EDS detector that allows Lithium detection.
With EELS and EDS, results for Li detection will be presented and the challenges, in regards ofquantification and beam damage, will be covered. Examples of EELS analysis at 30 keV for
nanomaterials will be presented, including surface plasmon. The SU-9000EA allows to perform
electron diffraction and CBED patterns acquired at the nanoscale will be presented.
As an example, figure 1 shows a LiCl specimen after an EDS spectrum was acquired. To detect the
Li K line after 200 second acquisition time, the specimen had to be damaged by the beam. Understandthe beam damage is critical for successful application of EDS for Li based materials.

Figure 1. LiCI specimen after the acquisition of
a EDS Spectrum. 200 S live time.

16 | P a g e

Progress on Multivariate Statistics to Improve Spectrum Image Interpretation
Nadi Braidy1,2*, Ryan Gosselin1
Chemical and Biotechnological Engineering, Université de Sherbrooke. 2500 Boul. de l’Université,
Sherbrooke, Québec, J1K 2R1, Canada
2Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke. 3000 Boul. del’Université, Sherbrooke, Québec, J1K 0A5, Canada.
*nadi.braidy@usherbrooke.ca
1

TEM spectrum images are typically processed using background removal and peak-integration
techniques. Latent variable models such as principal component analysis (PCA) and multivariate curve
resolution alternating least-squares (MCR-ALS) are becoming interesting alternatives capable ofresolving complex mixtures into pure component contributions. Recently [1,2], we proposed a new
method for the analysis of low-count spectrum images [1] in which the multilinear regression step ofthe MCR-ALS is replaced by the Log-Likelihood Maximization (MCR-LLM) under spectral
constraints based on Poisson noise characteristics.
We demonstrate the advantages of using the MCR-LLM method for the analysis of several
datasets, including an EELS spectrum-image of ferrite nanoparticles exhibiting surface segregation (Fig
1, [3]), a simultaneously recorded EELS-EDX linescan from a transistor stack, and an EDX map from a
III-V nanowire. Once the components are isolated, it becomes straightforward to conduct elemental andquantitative analyses. In addition to enabling the extraction of meaningful spectral components (unlike
PCA), the MCR-LLM method makes it possible to carry out analyses of low signal-to-noise ratio
dataset and co-registered datasets. For each instance, we will detail the analytical strategy and discuss
the added value of such an approach and possible pitfalls.
References:[1] Lavoie, F. B., Braidy N. & Gosselin, R. Including noise characteristics in MCR to improve
mapping and component extraction from spectral images. Chemometrics and Intelligent Laboratory
Systems 153 (2016), 40[2] Braidy, N. & Gosselin, R. Unmixing noisy co-registered spectrum images of multicomponent
nanostructures. Scientific Reports 9, (2019), 1[3] Li, A. Y., Dumaresq, N., Segalla, A., Braidy, N. & Moores, A. Plasma-Made (Ni0.5Cu0.5)Fe2O4
Nanoparticles for Alcohol Amination under Microwave Heating. ChemCatChem 11, (2019), 3959
Figure 1. A) Scanning-TEM
image of (Cu,Ni)-ferrites
decorated with Cu0 B) EELS
elemental distribution
computed with standard
windowing methods (red =Cu, green = Ni+Fe) C)
EELS elemental distribution
with hierarchal multivariate
statistics methods [3].

17 | P a g e

Data-Driven Electron Microscopy Reveals Shape-Dependent Subpercent Strains inGold Nanorods
Kohei Aso1*, Jens Maebe2, Xuan Quy Tran3, Tomokazu Yamamoto4, Yoshifumi Oshima1, and Syo
Matsumura3,4
1

School of Materials Science, Japan Advanced Institute of Science and Technology, Asahidai 1-1,
Nomi, Ishikawa, 923-1292, Japan
2
Faculty of Sciences, Ghent University, Krijgslaan 281-S2, 9000 Ghent, Belgium
3
Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka 744,
Nishi-ku, Fukuoka 819-0395, Japan
4
The Ultramicroscopy Research Center, Kyushu University, Motooka 744, Nishi-ku, Fukuoka 8190395, Japan*
aso@jaist.ac.jp
In nanomaterials, the physical properties are sensitive to the shape due to the large surface-tovolume ratio. The strain distribution in the nanoparticles with anisotropic shape has been expected to be
non-uniform. However, such experimental results have not been reported so far, which is probably
because of a lack of precision in strain analysis. In this study, we established a method to estimate thestrain distribution of gold (Au) rod precisely from the atomic-resolution scanning transmission electron
microscopy (AR-STEM) images by data-driven analysis and clarified the relationship between strain
distribution and the shape of Au nanoparticles.
We observed three Au nanoparticles of 9 nm in diameter but different rod lengths (9 nm, 21 nm,
and 36 nm) including a sphere by AR-STEM. Figure 1a shows a nanorod with a length of 21 nm. The
ten images acquired with fast scan (1 μs/pixel) were integrated into one image, to minimize both theeffect of noise and instability of equipment.
Inter-columnar distances were measured from the AR-STEM images. The raw data from the coreregion surrounded with a rectangle in Fig, 1 contained noise components of random fluctuations up to~1.2 %. The Gaussian process regression (GPR) was applied to remove the noise components andthe precision in local strain analysis was improved to 0.2 %.
We found that the rod-shaped nanoparticle had peculiar local strain distribution. Figure 2 showsa map of the strain of the (001) lattice spacing for the Au rod and sphere, where the (001) lattice isperpendicular to the horizontal direction in Fig. 2. In the case of the spherical particle (Fig. 2a), the latticeshows contraction near the surface (dark blue on the map), which is reasonable because of surface
contraction. On the other hand, a lattice expansion (bright yellow on the map) of ~ +0.6% was discoverednear the tip of the rod-like nanoparticle (Fig. 2b) [1,2].
References:[1] K. Aso, et al., Microscopy, Vol. 65 (2016), page 391–399[2] K. Aso, et al., ACS Nano, Vol. 15 (2021), page 12077–12085

Fig. 1 AR-STEM image of a nanorod. Fig. 2 Strain exx(x,y) maps of (a) a sphere and (b) the rod. Scalebars are 2 nm.

18 | P a g e

Mapping electrostatic potential gradient in GaN NW p-n junctions using electron holography.
Anitha Jose1*, Alex Mingze Yang1, Qihua Zhang2, Songrui Zhao2, and Karen L. Kavanagh1
1Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
2
Department of Electrical and Computer Engineering, McGill University, Montreal, Québec, H3A
0E9, Canada.
*anithaj@sfu.ca
GaN nanowires (NWs) have been applied in devices including light emitting diodes (LEDs) [1],photodetectors [2] and laser diodes [3]. Understanding and controlling dopant incorporation is crucial
for improving device performance. However, precise measurement of the dopant distribution in devices
has been a difficult task [4]. Electron Holography (EH) is a technique that allows the quantitative
determination of the electrostatic potential in a material [5] and therefore gives us a better understandingof the actual doping in the system.
We report the characterization of GaN nanowire (NW) axial p - n junctions by quantifying the built-in
voltage and depletion width using off-axis EH. NWs were grown by Molecular Beam Epitaxy using Si
and Mg as the n-type and p-type dopant respectively (ND = 1018 cm-3 and NA = 1019 cm-3). SEM imageof the NWs showed a clear change in contrast suggesting the presence of a junction. The junction position
was 200 nm from the top. Fig 1 (c) shows a longitudinal profile from the reconstructed phase image in(a), detecting an increase in phase from the p to n region. The corresponding potential profile estimateda built-in voltage (Vbi) of 1.0 ± 0.1 at the junction, assuming a hexagonal model. The depletion width
was found to be 31 ± 2 nm. The values of Vbi obtained from different NWs ranged from 1.5 ± 0.2 V to
0.9 ± 0.1 V. No stacking faults were detected as shown in BF TEM in (b). The expected Vbi,, assuming
100% activation is 3.2 V. More experiments are underway to measure Vbi as a function of different dopant
concentrations.
References:[1] C.-Y. Chen et al, ACS Nano, 6, (2012), 5687-5692.
[2] X. Zhang et al, J. Mater. Chem. C, 5, (2017), 4319-4326.
[3] J. Heo et al, Appl.Phys. Lett., 98, (2011), 21110.
[4] Wallentin et al, J. Mater. Res., 26, (2011), 2142.
[5] M. Lehmann and H. Lichte, Microscopy and Microanalysis, 8, (2002), 447.
(a)

(b)

(c)

Figure 1: (a) Phase and (b) BF image with (c) a corresponding phase and potential profiles along
the length of the wire. The profiles are an average within the white box in (a).
19 | P a g e

Capturing the moment of nucleation and tracing the crystal growth by SMART-EM
Takayuki Nakamuro1*, Masaya Sakakibara1, Hiroki Nada2, Koji Harano1, Eiichi Nakamura1
1

Department of Chemistry, The University of Tokyo, Tokyo 113-0033, Japan.
Environmental Management Research Institute, National Institute of Advanced Industrial Science andTechnology (AIST), Tsukuba 305-8569, Japan*
muro@chem.s.u-tokyo.ac.jp
2

Crystallization is essentially a stochastic process, and experimental studies of the mechanism
have been difficult. Our research group has been developing a molecular electron microscopy
technique called "single-molecule atomic-resolution time-resolved electron microscopy (SMART-EM)1
imaging," which allows us to record the dynamic behavior of individual small molecules, as well as ofmolecular assemblies. In this study, by combining the SMART-EM imaging method with a newly
developed sample preparation method, we have succeeded in continuously imaging and analyzing theprocess of spontaneous assembly of sodium chloride (NaCl) molecules to form crystal nuclei and thengrow into crystals.2
We captured the moment when NaCl crystal nuclei of about 1 nm in size repeatedly formed at
the tip of the carbon nanohorn (CNH), and it became clear that the pre-nucleation molecular aggregateswere moving back and forth between a crystal-like ordered structure and a disordered structure bydisassociation and aggregation (Figure 1) Details of this mechanism will be discussed in thepresentation.
In summary, we developed a new microscopy technique for the common phenomenon of
crystallization (Figure 2), and analyzed the mechanism at the molecular level.
References:[1] E. Nakamura, Acc. Chem. Soc. 2017, 50, 1281−1292.
[2] T. Nakamuro, M. Sakakibara, H. Nada, K. Harano, E. Nakamura, J. Am. Chem. Soc. 2021, 143,
1763−1767.

Fig. 1 Summary: TEM observation of NaCl units
aggregating into crystals at the tip of a CNH.

20 | P a g e

Fig. 2. YouTube links to videos related to thispresentation.

Phase Imaging Electron Intensities on the Diffraction Plane
Rodney A Herring, MENG, CAMTEC, University of Victoria, Victoria, B.C. Canada V8W 2Y2
A method to interfere electron intensities on the diffraction plane invented during the Tonomura
Electron Wavefront Project [1], somewhat surprisingly, reveals all sources of intensity, i.e., elasticallyand inelastically scattered, have sufficient coherence to form fringes enabling the measurement of theirphases. For example, using the self-interference of elastically-scattered HOLZ line intensities was used
to measure the three-dimensional strain distribution through the crystals making it possible to solve theHowie-Whelan equation [2, 3]. Interfering symmetric Bragg diffraction beams measured the strain
profile at dislocation cores where the 2π phase shift produces a physical singularity at its center, possibly
the smallest in existence [4]. More recent observations revealed residual two dimensional lattice phase
images where a flat phase image was expected possibly due to dynamic diffraction, Fig. 1 [5]. If true,
dynamic diffraction can be studied as a function of specimen thickness, diffracted beam extinction
distances and deviation parameter from exact Bragg diffraction. These studies will be presented for
discussion during the workshop.
References
1. Tonomura Electron Wavefront Project (1989 – 1994), Exploratory Research for Advanced
Technology (ERATO), Japan Science and Technology Corporation, Kawaguchi Center Bldg.,
4-1-8, Honcho, Kawaguchi-shi, Saitaima 332 Japan.
2. Herring, R.A., M. Norouzpour, K. Saitoh, N. Tanaka, and T. Tanji, “Determination of threedimensional strain state in crystals using self-interfered split HOLZ lines” Ultramicroscopy 156(2015) 37-40.
3. Norouzpour, M. and R.A. Herring, “Aberration-corrected self-interference of split higher order
Laue zone Line for measuring the z-dependent strain profile” J. Mater. Res., Vol. 32, No. 5,(2017) 996 – 1008.
4. Herring, R.A., “Phase Imaging Dislocations using Diffracted Beam Interferometry”
Microscopy (2020) MICRO-2020-00047.
5. Herring, R.A., “Dynamic Diffraction Lattice Phase Imaging Using DBI” Microsc. Microanal.
27 (Suppl 1), (2021) 2194/5.

Fig. 1 – a) DBI phase image of the interference of symmetrical Bragg diffracted beams of Au showing
an amorphous C (a-C) deposit with its phase spectrum passing through the line in the upper right corner,a dislocation network at D and the residual phase, R, in the perfect crystal magnified in b) and its phase
spectrum along the line shown in c) clearly revealing the complex phase shift’s periodicity.

21 | P a g e

Application of 4D-STEM at 30 kV for structure analysis of block co-polymers and highresolution multi-slice phase retrieval
Arthur M. Blackburn1*, Cristina Cordoba1, Robert McLeod2, Yifan Zhang1 and Ian Manners1
1

University of Victoria, 3800 Finnerty Road, Victoria, BC, V8W 2Y2, Canada
Hitachi High-Tech Canada Inc., 89 Galaxy Blvd, Etobicoke ON, M9W 6A4, Canada*
ablackbu@uvic.ca
2

Scanning transmission electron microscopy (STEM) at 30 kV combined with low angle annulardark field (LAADF) detection can provide strong in-focus image contrast on weak contrast polymer
materials. In comparison to higher beam energy TEM, it offers some stronger beam-sample interactions
and may reduce some beam induced damage mechanisms. Furthermore, 30 kV STEM imaging can be
performed in SEM class instruments which generally offer greater ease of use and reduced cost. In thiswork we integrated a high-speed direct detection camera to a SEM type instrument (Hitachi SU9000), toenable the rapid collection of low-dose four dimensional (4D)-STEM data sets, where a diffraction
pattern is collected at each scanned position. This is exemplified here with the collection of 10000
diffraction patterns (DPs), each with a 10 ms exposure from a 20 × 20 µm field of view, to yield a nonsample destructive average electron dose of 17 e-/Å2. These conditions provided new insights into thestructural origins of branching within specific block co-polymers [1], an example of which is in Fig. 1a.
Here DPs (Fig 1b, c) obtained from the central and branch regions differ, indicating an additional
nucleation site at the branch point.
Additionally, we show 4D-STEM data sets obtained in this instrument, using only simple
projection optics, can be processed using multi-slice ptychographic algorithms to allow 50 pm (or better)features to be resolved at 30 kV (Fig 2a, b). Though electron ptychography was first experimentallydemonstrated at 30 kV [2] showing 236 pm lattice fringes, relatively little exploration of ptychography
at this energy has been pursued since then, particularly with the direct electron detectors, such as the oneused in this work (Dectris Quadro). We thus summarize that a high-speed pixelated direct electron
detector on a low kV SEM/STEM instruments provides great utility in the structural characterization ofdose sensitive materials and provides access to high-resolution phase imaging through ptychography.
[1] Y. Zhang, S. Pearce, et al., J. Am. Chem. Soc., Vol. 143, (2021), 5805-14.
[2] M. J. Humphry, B. Kraus, et al., Nature Comms., Vol.3, (2003), 730.

Fig. 1 (a) LAADF image of a typical branchedblock co-polymer, where (b) a DP collected fromthe branching region shows dual patterns and (c)the central region DP shows a single pattern.

22 | P a g e

Fig. 2. (a) Reconstructed phase (30 kV) of gold
particles on carbon film from ptychography and (b)its FFT, with strong diffraction ring indices labelled
and 50 pm peaks encircled.

Visual Molecular Science at Interface of Self-Assembly and Electron Microscopy
Koji Harano1*
1

Department of Chemistry, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033,
Japan.
*
harano@chem.s.u-tokyo.ac.jp
It remains as a challenge to design functions of self-assembled materials in a predictable manner
because of the lack of understanding on self-assembly processes at a molecular level. We have developed
new electron microscopic methods named single-molecule atomic-resolution time-resolved electron
microscopy (SMART-EM) that provides information on the time evolution of the structures of individual
molecules and self-assembled molecules. The key is that we observed little sign of decomposition of thespecimen molecules encapsulated in or attached to a single-walled carbon nanotube (CNT) as opposed
to solid organic materials. The high specimen stability and the real-time movie recording enable us to
study on the conformation of each carbon-carbon bond in single perfluoroalkyl fullerene molecules,
dynamic conformational changes of linear molecules, and structure of organic nanoclusters formed as aprecursor of a crystal nucleus from supersaturated solution. Recently we have demonstrated that the
SMART-EM video imaging provides a unique methodology for capturing and analyzing the minute
reaction intermediates, as illustrated for new host-guest binding modes of cyclodextrins (Fig. 1) andprenucleation clusters in the reaction mixture of metal–organic frameworks (Fig. 2). In this lecture, I
would also like to discuss the significance of in-situ observation of individual molecules in chemical
events using the high-speed molecular video imaging.
References: Nat. Mater. 11, 877–881 (2012). J. Am. Chem. Soc., 136, 466-473 (2014). J. Am. Chem.
Soc., 137, 3474–3477 (2015). J. Am. Chem. Soc., 139, 18281–18287 (2017). Nat. Commun., 10, 3608
(2019). Bull. Chem. Soc. Jpn. 93, 1079–1085 (2020). Bull. Chem. Soc. Jpn. 93, 1603–1608 (2020).
Microsc. Microanal. 26, 667–675 (2020). J. Am. Chem. Soc. 143, 1763–1767 (2021). J. Am. Chem.
Soc. 143, 5786–5792 (2021). ACS Nano 15, 12804–12814 (2021). arXiv 2107.01490.

Fig. 1 Statistic TEM image analysis of
cyclodextrins bound to spherical tips of carbon
nanotubes, demonstrating the existence of a rim
binding mode in addition to the conventional
cavity binding to cyclodextrins.

23 | P a g e

Fig. 2. Capturing and TEM imaging of reaction
intermediates from a mixture of metal-organic
framework synthesis by using a chemicallyfunctionalized carbon nanotubes as “fishhook” for anucleating cluster.

Contribution of microstructure in oblique impact morphology of high entropy CrMnCoFeNi
particles
Roghayeh Nikbakht *Mechanical engineering Department, University of Ottawa, Ottawa, ON, Canada
roghayeg.nikbakht@uottawa.ca
Cold spray is a powder consolidation method at which micron size particles are accelerated tohigh velocities (300-1200 m/s) and deposit to a substrate as a result of plastic deformation and nativeoxide removal [1, 2]. Microstructure of powder particles plays an important role in oblique impact
morphology. In this study CrMnCoFeNi high entropy alloy (HEA) particles were sprayed on Nickel
substrates using Helium as a process gas (3.2 MPa and 400 ˚C). The morphology and microstructure of
the single particles were analyzed using tilted view SE images, electron channelling contrast imaging(ECCI) (EVO MA-10, Carl Zeiss), and EBSD analyses (SU-8230 Hitachi cold field emission).
A gas atomized spherical CrMnCoFeNi powder with a cellular structure is used for singleparticle experiments (Fig. 1(a)). The ECCI maps of the cross-sections of two powder particles show two
different morphologies: one with elongated grains and one with relatively equiaxed structure (Fig. 1(a1)and (b1)). The deformed particles morphology change from perfect half-sphere with jetting zones locatedat the lips (Fig.1(a2)), to half sphere morphology with some protuberances in the rim of the half-sphere(Fig.1(b2)). ECCI maps and IPF maps of two CrMnCoFeNi particles in Fig. 1(a2-a3) with an equiaxed
grain distribution presents a symmetrical half-sphere impact morphology while the particle of Fig. 1(b2b3) with elongated morphology deviates from symmetrical half-sphere morphology and is closer to a
top-hat morphology. KAM maps (Fig. 1(a4-b4)) demonstrate a higher degree of misorientation at grainboundaries of elongated grains which implies that grain boundaries are involved in the variation ofparticle impact morphologies by affecting the mechanism of plastic strain transfer or slip transfer(transmission) between particle grains. The generated dislocations at the lower part of the particles canmove easily inside the elongated grains –or toward the free surface of the particle in this case - without
being forced to transmit to the neighbouring grains (see Fig 1 (b4)). Microstructure variation of powder
particles may result in different impact physics and ultimately impact morphology.
References:[1] R. Nikbakht, S.H. Seyedein, S. Kheirandish, H. Assadi, B. Jodoin, Asymmetrical bonding in cold spraying of dissimilarmaterials, Appl. Surf. Sci. 444 (2018) 621-632.
[2] R. Nikbakht, H. Assadi, B. Jodoin, Intermetallic Phase Evolution of Cold-Sprayed Ni-Ti Composite Coatings: Influenceof As-Sprayed Chemical Composition, J. Therm. Spray Technol. 30 (2021) 119–130[3] R. Nikbakht, M. Saadati, H. Assadi, K. Jahani., and B. Jodoin, Dynamic microstructure evolution in cold sprayed NiTi
composite coatings, Surf. Coat. Technol, (2021) 421, p.127456.

Figure 1. Effect of particle microstructure on impact morphology. (a) morphology of powder particle,(a1-b1) ECCI maps of cross-section of CrMnCoFeNi alloy particles, (a2-b2) morphology of depositedparticle, (a3-b3) ECCI map of cross-section of particles, (a3-b3) IPFs maps and (a5-b5) KAM maps.

24 | P a g e

Atomic bond stiffness in Pt atomic chains measured by TEM coupled with a quartz LER
Yoshifumi Oshima1*, Jiaqi Zhang1, Masahiko Tomitori1
1
Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, 923-1292, Japan.
*
oshima@jaist.ac.jp
Monatomic chains have shown unique physical and chemical properties, which draws a different
picture from their bulk counterparts. It has been reported that the electrical or magnetic properties can betuned by controlling the length of the atomic chains, which indicate that the mechanical properties is very
important for their applications. However, the mechanical properties of atomic chains have not beenclarified experimentally. To solve this problem, we developed an in-situ TEM holder equipped with aquartz resonator as force sensor (Fig. 1a) [1] to measure the mechanical properties of atomic chains whenobserving their atomic configurations.
A quartz length-extension resonator (LER) was used to measure the stiffness of platinum (Pt)monatomic chains from its frequency shift. Because the stiffness of the atomic chain suspended between
the edge of LER and the fixed counter base can be measure precisely with very small oscillation
amplitude (about 30 pm). The atomic resolution TEM images (Fig. 1b) and videos were captured
simultaneously with measuring the conductance and stiffness by our developed TEM holder.
The stiffness of atomic chains with 2-5 atoms were obtained (Fig. 1c). By subtracting the stiffness ofthe electrodes supporting the monatomic chain
from the measured stiffness, we found that the
stiffness of a Pt monatomic chain varied with thenumber of the constitute atoms in the chain. We
investigated the stiffness of about 150 Pt
monatomic chains for reproducibility andconfirmed that the middle bond stiffness (25N/m)in the chain was slightly higher than that of thebond connect to the suspending tip (23N/m). In
addition, the maximum elastic strain of individualbond in the chain was as large as 24% [2]. These Fig. 1. (a) Schematic illustration of thevalues were obviously different from the bulk experimental setup. (b) TEM image of at atomic
counterpart. Such peculiar values could be briefly chain with 4 atoms and corresponding atomic
explained by the concept of “string tension”.
configurations of the chain. (c) Stiffness
histograms of the Pt monatomic chains.
References[1] J. Zhang et al, Nanotechnology. 31 (2020) 205706.
[2] J. Zhang et al, Nano letters. 21 (2021) 3922-3928.

25 | P a g e

Thermal Evolution of Alloying State in Ternary IrPdRu Nanoparticles
Xuan Quy Tran 1*, 山本知一 (Tomokazu Yamamoto)2, 松村 晶 (Syo Matsumura)1,2
草田康平 (Kohei Kusada)3, 吴 冬霜 (Dongshuang Wu)3, 北川 宏 (Hiroshi Kitagawa)3
1

Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka 744, Nishiku, Fukuoka 819-0395, Japan.
2
The Ultramicroscopy Research Center, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan.
3
Department of Chemistry, Kyoto University, Kitashirakawa-Oiwakecho, Kyoto 606-8502, Japan*
tran.xuan.quy.044@m.kyushu-u.ac.jp
Compositional and structural arrangements of constituent elements, especially those at the surface andnear-surface layers, greatly influence the catalytic performance of alloyed nanoparticles (NPs). The
compositional stability and associated structural evolution of a ternary Iridium–Palladium–Ruthenium (IrPdRu)
nanoalloy at elevated temperatures have been studied using interrupted in-situ scanning transmission electron
microscopy and theoretical modeling [1].
Equiatomic solid-solution nanoalloys of IrPdRu were synthesized via a modified polyol method where themetal precursors (K2PdCl4, RuCl3.nH2O, and IrCl4.nH2O) dissolved in deionized water were added to a triethylene
glycol solution heated at 230 °C using PVP as a protecting agent. The NP samples were dispersed in ethanol andwere dropcasted onto the carbon-supported membranes of MEMS E-chips. Structural analysis was performed on
a JEOL JEM-ARM200CF operated at 200 kV with an Aduro heating holder (Protochips). Canonical Monte Carlo(MC) simulations were performed for a NP model containing N = 5,793 atoms (~5.6 nm in size) based on the
Metropolis algorithm to gain atomistic insights of the compositional evolution. The total energy of the model
during the MC simulations was continuously evaluated using the molecular dynamics library LAMMPS and ourdeveloped EAM potential for IrPdRu.
Figure 1 tracks compositional time-evolution of IrPdRu NPs annealed at 500 oC using composite XEDS
maps and the corresponding Gibbs triangles [2]. In the latter, the center of the compositional profiles slightly
displaces from the original position toward the Ir-Ru edge. In a NP model given in Fig. 2, there is a cumulative
coverage of Pd atoms in the surface, while Ir and Ru atoms remain mixing in the core region, shifting the composition center in the Gibbs triangle in a similar manner as in Fig. 1.
References:[1] X. Q. Tran, et al., ACS Nano, submitted for publication[2] X. Q. Tran, et al., J. Phys. Chem. C, 124 (2020), 21843.

Fig. 1. Tracking the sub-nm compositional
Fig. 2. Canonical MC simulations for a IrPdRu
evolution in a IrPdRu particle cluster annealed at particle model (~5.6 nm) at 500 oC, and Gibbs
500 oC in terms of XEDS maps and corresponding triangle representation of the local compositional
Gibbs composition triangles.
sampled from 2D pixel columns of 0.7×0.7×l nm3.

26 | P a g e

Utilization of Correlative Light and Electron Microscopy for Analyzing the Structural
Organization of Bacterial Microcrystalline Cellulose
Alyssa Williams1; Mouhanad Babi2; Marcia Reid4; Kathryn Grandfield1,3; Nabil Bassim1,3,4; Jose MoranMirabal2,51School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada
Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON, Canada
3
Department of Materials Science and Engineering, McMaster University, Hamilton, ON, Canada
4
Canadian Center for Electron Microscopy, McMaster University, Hamilton, ON, Canada
5
Centre for Advanced Light Microscopy, McMaster University, Hamilton, ON, Canada
2

Cellulose’s mechanical strength and bioavailability have contributed to its prominent use in industrial
applications where it undergoes biochemical processing including depolymerization [1]. In the cellulose
microfibril structure, disordered regions or “dislocations” along the fibril have been characterized as key
sites for cellulose degradation [2]. In this correlative light and electron microscopy (CLEM) workflow,
the specificity and localization precision of super-resolution imaging (SR) and the nanoscale highresolution imaging from transmission electron microscopy (TEM) were used to investigate and elucidate
ultrastructural details of the bacterial microcrystalline cellulose (BMCC) microfibril structure. For
CLEM imaging, a sample preparation method has been adapted, where Cy5 labelled BMCC microfibrils
were prepared on TEM alphanumeric finder grids with imaging buffer and placed in between coverslips
for direct stochastic reconstruction microscopy (dSTORM), an SR imaging technique, using a Leica
DMI6000 B microscope (Fig 1.a)) [3]. Due to the accessibility of dislocation areas on the microfibrils,
Cy5 binds and aggregates in these regions. Thereby, indicating the presence of a dislocation on the
microfibril. BMCC microfibrils of interest were identified from the dSTORM images and located on thefinder grid. The TEM grids were then washed and dried to be made vacuum compatible for TEM
imaging. BMCC microfibrils were identified and imaged at the nanoscale in bright field TEM imaging
on a JEOL JEM 1200EX TEMSCAN microscope (Fig 1.b)). Adobe photoshop was utilized to overlay
SR and TEM images (Fig 1.c)). Analysis of composite image revealed that dislocation areas (bright Cy5
spots) on the BMCC microfibril appear to overlap with fibril twisting regions (darker regions).
References:[1]
Lynd et al., Microbiol Mol Biol Rev, Vol. 66, (2002), 506-577.
[2]
Hidayat et al., Cellulose, Vol. 19, (2012), 1481–1493.
[3]
van Elsland et al., Chembiochem, Vol. 19, (2018), 1766-1770.

27 | P a g e

Manual versus automatic analysis of microglial spatial characteristics: a comparison in the
hippocampus of healthy adult mice
Mohammadparsa Khakpour1, Fernando González Ibáñez2, Maude Bordeleau2,3, Laura Maggi4,Marie-Ève Tremblay1-3,5-6
Corresponding author email: Parsa.khakpour2000@gmail.com
1

Division of Medical Sciences, University of Victoria, Victoria, BC, Canada; 2 Axe Neurosciences, Centre derecherche du CHU de Québec-Université Laval, Québec, QC, Canada; 3 Neurology and Neurosurgery Department,
McGill University, Montréal, QC, Canada; 4 Department of Physiology and Pharmacology, Istituto PasteurFondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy; 5 Department of Molecular Medicine,
Université de Laval, Québec City, QC, Canada; 6 Department of Biochemistry and Molecular Biology, University of
British Columbia, Vancouver, BC, Canada;

Image analysis is a powerful tool in neuroscience. Many approaches in image analysis still dependon manual identification and tracking of biological events. This manual approach can introduce
personal bias and require long sessions of work. Automatization of analytical processes represents
a potential solution for bias and time investment. Methods that optimize the analysis quality byincreasing efficiency and reducing bias are favored. To establish such a methodology, a microcommand was developed that runs on ImageJ to apply image analysis. However, the provided
micro command requires to be validated and compared with the manual analysis to assess theperformability of automatic analysis for microglia research. Microglia are immune cells foundthroughout the brain parenchyma. Recent studies suggested that microglial spatial characteristics(e.g. density) are not homogeneous between different brain regions. Microglial spatial
characteristics analysis provides valuable information on their various functions. Manually
recognizing individual cells is the subject of time-consumption and bias. The script performs
microglial cell body selection in brain regions that are manually traced for the spatial analysis. The
main core of the micro script consists of four sections. The script involves the cell selection
assessment and executes automatic spatial analysis for each individual cell. The data generated
with this workflow provides spatial characteristics measurement. The current study focused oncomparing manual versus automatic analysis directly to found out whether the automatic analysis
is efficient enough to replace the manual analysis. The command is a groundbreaking instrumentthat reduces the analysis time length, produces valid data, and decreases the sensitivity to possible
bias.

28 | P a g e

Belief theory enables detection of Caveolae in superresolution microscopy.
Ben Cardoen1*, Timothy Wong2, Ivan Robert Nabi2**, Ghassan Hamarneh1**1

Medical Image Analysis Research Group, Simon Fraser University, British Columbia, Canada
Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British
Columbia, British Columbia, Canada*
bcardoen@sfu.ca**
Equal contribution
Supported by CIHR grants PJT-159845, PJT-156424 and PJT-175112
2

We developed a novel method[1] that enables the automatic detection of CAV1 structures in
STED super resolution microscopy.
Our method detects objects automatically across images with varying intensity profiles, then uses
the cell level label to build a model that identifies which objects are discriminating for each cell type.
Our model leverages belief theory to automatically learn a per object label, with lower and upper boundprobabilities, including the uncertainty in identification of each object. We identify Caveolae andscaffolds, two types of CAV1 protein complexes, that are key to preventing membrane breakage of thecell membrane in response to stress. Our results match identification of CAV1 structures in fixed cells
imaged using dSTORM[2]. Our STED based method enables the detection in live cells, where theformation dynamics can be observed and extracted.
References:[1] Cardoen, B., Wong, T., Alan, P., Lee, S., Matsubara, J.A., Nabi, I.R. and Hamarneh, G., 2020.
SPECHT: Self-tuning Plausibility Based Object Detection Enables Quantification of Conflict inHeterogeneous Multi-scale Microscopy.
[2] Khater, Ismail M., Qian Liu, Keng C. Chou, Ghassan Hamarneh, and Ivan Robert Nabi. "Superresolution modularity analysis shows polyhedral caveolin-1 oligomers combine to form scaffolds andcaveolae." Scientific reports 9, no. 1 (2019): 1-10.

Figure 1: Identification of CAV1 protein complexes in STED superresolution microscopy. The
identified Caveolae show the expected colocalization with Cavin1 (B). Our model uses 3 cell level
labels to build its discriminatory capability (D). Figure based on original from [1].

29 | P a g e

TEM/STEM Intensity Modulation with Increasing Thickness
Induced by Electron Multiple Scattering Phenomena in Materials
山﨑 順(Jun Yamasaki)1,2*, 西久保 英郎(Hideo Nishikubo)3, 佐々木 宏和(Hirokazu Sasaki)3, 荒井
重勇(Shigeo Arai)2
1

Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1, Mihogaoka,
Ibaraki, Osaka567-0047, Japan.
2
Institute for Materials and Systems for Sustainability, Nagoya University, Japan.
3
Furukawa Electric Co., Ltd., Japan. *yamasaki@uhvem.osaka-u.ac.jp
Clarification of the thickness dependence of image contrast in transmission electron micrographs
is important for deep understanding of multiple scattering phenomena of high-energy electrons as well
as from the viewpoint of applications to various experiments, such as effective observations of thicksamples including in-situ experiments and quantitative electron tomography [1]. In the present study, theimage intensity in bright-field (BF-) TEM and ADF-STEM were analyzed for polystyrene, amorphous
carbon, and amorphous NiP as functions of thickness [2].
Figure 1 shows examples of the results, which were measured in BF-TEM images of polystyrene
taken with various beam energies. Contrary to the general understanding that the electron transmission
T decreases exponentially with increasing thickness (shown by broken straight lines in the log plot in
Fig. 1), the measured attenuations show curves attributed to multiple scattering phenomena [1, 2]. By
analyzing all the data obtained under a wide range of conditions (acceleration voltage of 200 kV–3 MV,
aperture acceptance angles of 0.85–30 nm-1, and thickness of 0.25–10 μm), it was found that they wereexpressed well by a function containing three parameters [2], as seen in the excellent fittings in Fig. 1.
We succeeded in expressing the attenuation function approximately based on a simple mathematicalmodel of the multiple scattering. Moreover, we found that also the thickness dependences of ADF-STEM
intensity obtained with various detection angles were successfully expressed by simple extensions of the
proposed function as shown in Fig. 2. The benefit to achieve quantitative electron tomography is also
discussed.
References:[1] J. Yamasaki, et al., Microscopy 63, 345 (2014).
[2] J. Yamasaki, Y. Ubata and H. Yasuda, Ultramicroscopy 200, 20 (2019).

Fig. 1. Intensity attenuations in BF-TEM imagesof polystyrene taken with various acceleration
voltages. All the data (color dots) are fitted well by
the proposed function (solid curves).

30 | P a g e

Fig. 2. ADF-STEM intensity of amorphous NiPtaken with 1000 kV. The measured intensity (bluedots) are fitted well by the extension of the
proposed function (red curve).

NanoMi: a Public-License Platform for Electron Microscopy Development and Education
Marek Malac 1,2*, M. Kamal1, K. Kumar2, J. A. Marin-Calzada2, M. Salomons1, D. Homeniuk1, D.
Vick1, R. Au2, A. Czarnecki2, D. Price1, M. Hayashida1, M. Cloutier1, R.F. Egerton2
1
2

NRC-NANO, 11421 Saskatchewan Dr., Edmonton, T6G 2M9, Canada.
Dept. of Physics, University of Alberta, Edmonton, T6G 2E1, Canada.

*

marek-malac@nrc-cnrc.gc.ca

We are developing a modular electron microscope column distributed under a public license [1,2],
referred to as NanoMi. Elements of modeling and control software are already freely available [2]. The
target for release of blueprints and circuit diagrams is late 2021.
NanoMi is intended to provide SEM, STEM, TEM and electron diffraction capabilities. NanoMi
is based on electrostatic Einzel lens and operates at up to 50 kV. Electron-optical components are
independent from the vacuum envelope, and are ultra-high vacuum (UHV) compatible. Fig. 1 shows aview of the NanoMi column internal arrangement. It is ~1300 mm tall in STEM / TEM configuration.
SEM functionality can be implemented with ~500 mm column height. Fig 2. shows the current layout of
the SEM probe-forming optics. Modeling suggests ~1000x source demagnification at the sample plane,
providing ~30 nm probe when using a W-hairpin source. We are testing and debugging SEM and STEM
hardware, electronics and software control. Simulation and control SW are written in Python and run ona single Linux PC.
NanoMi can be attached to an existing experimental apparatus, e.g. thin film growth system, tocustomize experiments. It can also provide a test bench for development of electron-optical components.
The use of electrostatic electron-optics reduces NanoMi’s heat load, could increase the scan speed in
SEM, and could allow the future use ions rather than electrons.
[1] M Malac et al. Microscopy and Microanalysis 26 (S2), (2020), 1810.
[2] NanoMi.org osf.io/bpj73/ github.com/NRC-NANOmi/NanoMi

Fig. 1 Photo of the NanoMi column and the Fig. 2. Interactive matrix optics layout for SEM
electron-optical “breadboard” of NanoMi. The probe formation. Currently, NanoMi comprises ofelectron source is located at the bottom. The use of three Einzel-type condenser lens at 232, 382 and 509
a breadboard concept to mount optical elements mm from the electron source. The sample plane isallows for convenient optics modifications.
located at 529 mm.

31 | P a g e

STEM-Moiré Applications to Crystalline Specimens without using High-End Microscopes
Junji Yamanaka1*, Chiaya Yamamoto1, Kosuke O. Hara2, Keisuke Arimoto2
1

Center for Inst. Analysis, University of Yamanashi, 4-3-11 Takeda, Kofu, JAPANCenter for Cry. Sci. & Tech., University of Yamanashi, 7-32 Miyamae, Kofu, JAPAN*: jyamanak@yamanashi.ac.jp, corresponding author
2Studies about STEM moiré, which is a moiré between scanning lines of STEM and crystal lattice, areprogressing recently [1-4]. It is very useful to analyze lattice strains in semiconductor materials and it is expected
to use for many other crystalline materials. Our group has been focusing on the usage of STEM moiré without
using highly specified machines, because we think that may contribute to many researchers in the field ofmaterials sciences [5, 6]. In this presentation, we will summarize and report our previous experimental results
about STEM moiré.
A field-emission type STEM (FEI Tecnai Osiris) without any Cs correctors was utilized with anacceleration voltage of 200 kV in this study. We observed the STEM moiré between the incidental-electron
scanning lines and the {111} planes of the Si, SiGe, and Ge. Fig. 1 shows STEM bright field image of the SiGe /Si (110), as a typical example of the STEM moiré. As a simple usage of this method, it is useful to distinguishcoherent/incoherent interfaces. This method also has potential to analyze crystal-plane spacings and directions.
One important point is that we don’t need high-end TEM such as Cs-corrected machines.
References:[1] S. Kim et al., Appl. Phys. Lett. 102 (2013) 161604.
[2] Y. Kondo and N. Endo, Kenbikyo 49 (2014) 226, in Japanese.
[3] A. Ishizuka et al., J. Electron Microsc. 66 (2017) 217.
[4] A. Pofelski et al., Ultramicroscopy 223 (2021) 113225[5] Junji Yamanaka et al., J. Mat. Sci. & Chem. Eng., 5 (2017) 102.
[6] Junji Yamanaka et al., Microsc. Microanal. 25 (Suppl 2) (2019) 242.

Fig. 1 STEM bright field image of the SiGe / Si (110). STEM moiré pattern is observed. A slight changeof the moiré direction among different layers can be seen. This includes the information of the slightchange of the crystal-plane spacing.

32 | P a g e

Development of Electron Microscopy toward Analysis of Optical and Quantum Effects in
Nanomaterials.
A. Maigné1*, S. Patankar1, G. Sawatzky1,2, A. Nojeh 1,3
1

Stewart Blusson Quantum Matter Institutem, University of British Columbia, Vancouver, Canada.
Department of Physics and Astrophysics, University of British Columbia, Vancouver, Canada
3
Department of Electrical and Computer Engineering, University of British Columbia, Vancouver,
Canada*alan.maigne@ubc.ca
2

In low-dimensionality objects such as nanowires and nanoparticles, material properties are drastically
influenced by confinement effects. New physics rules the electronic and optical properties, which makedesigning and understanding nanomaterials so complex yet so appealing. For example, nanotube forests
exhibit unique thermionic properties, and nanoparticles’ optical response changes drastically with theirsize and surface chemistry. Understanding and tuning those effects is the key to designing nanoparticles
and nanowires for applications such as quantum computing, solar cells and water treatment. Becausecharacterizing such phenomena requires a combination of energy, momentum and spatial resolution, it
remains extremely challenging.
During this presentation, we will discuss how to probe optical and quantum effects in a scanningtransmission electron microscope through the use of momentum-resolved electron energy loss
spectroscopy and cathodoluminescence.

33 | P a g e

TEM at Millikelvin Temperatures: What Would It Be Useful for?
Hiroshi Okamoto1*, Reza Firouzmandi2, Shota Uchita1, Vahid Sazgari2 and Ismet I. Kaya2
1

Department of Intelligent Mechatronics, Akita Prefectural University, 84-4, Aza Ebinokuchi,
Tsuchiya, Yurihonjo, Akita 015-0055, Japan
2
Faculty of Engineering and Natural Sciences, Sabancı University, Orhanli-Tuzla, Istanbul 34956,
Turkey*okamoto@akita-pu.ac.jp
Much attention has been paid to experiments involving optical photons and free-space electrons
recently [1]. Here we argue for potential interest and utility of microwave photons in this context anddescribe our effort being undertaken. As a result of extensive research in superconducting quantum
computing [2], exquisite control over microwave photons is possible today [3]. Moreover, interaction
between microwave photons and electrons could enable a rather unexpected application, namely highresolution biological electron cryomicroscopy [4].
The central aspect of superconducting qubits that interests us is their ability to generatequantum-mechanically superposed electromagnetic fields around them. This would result in aninteresting and exploitable interaction with flying electrons. For instance, a flux-qubit, in which an
electric current as large as 1 μA could flow in both clockwise and counterclockwise manner at the sametime, produces a superposed magnetic field around it. Another possibility, unique in microwave
frequencies, is to generate a superposed state of two very distinct electromagnetic fields involving≈ 100 photons using the so-called bosonic qubit [3]. The latter possibility may be more practical forreasons to be detailed in the talk.
"Seeing" such a superposed electromagnetic field with a TEM would certainly constitute an
intriguing physics experiment on its own. The price to pay is the necessity of millikelvin temperatures
to ensure ℏ𝜔 > 𝑘𝐵 𝑇, where 𝜔 ≈ 10 GHz is the microwave photon frequency. For this purpose, a3
He/4He dilution refrigerator must be inserted in the TEM. Nonetheless, such effort may be amply
rewarded because we do know a way to exploit electron-qubit interaction to eventually enable"quantum electron microscopy" of beam-sensitive
biological specimens [4].
A project involving a TEM combined with adilution refrigerator would be costly. For proof-ofprinciple purposes, instead we plan to place an "ultrasmall
TEM" in a commercial dilution refrigerator. Developmentof such a small TEM, their test equipment, as well as
superconducting devices, is underway (Fig. 1).
We thank Y. Okuda, Y. Takayama and S. Miurafor their early contributions to the development of ourexperimental setups. This research is supported in partby the JSPS "Kakenhi" grant (Grant No. 19K05285).
Fig. 1. Low temperature test equipment underconstruction. Inset: A Josephson device.

References:[1] See e.g. K. Wang et al., Nature 582 (2020), 50–54; O. Schwartz et al., Nat. Methods 16 (2019)
1016-1020.
[2] For a recent review, see e.g. P. Krantz et al., Appl. Phys. Rev. 6 (2019) 021318.
[3] See e.g. B. Vlastakis et al., Science 342 (2013) 607-610.
[4] H. Okamoto, PRA 85 (2012) 043810; H. Okamoto and Y. Nagatani, APL 104 (2014) 062604; H.
Okamoto arXiv:2001.05603v3 [quant-ph].

34 | P a g e

Higher-order structure of barley chromosomes observed by Electron Tomography.
Misa Hayashida1*, Channarong Sartsanga2, Rinyaporn Phengchat2, Marek Malac1,2, Kiichi Fukui4,
Nobuko Ohmido2
1

Nanotechnology Research Centre, National Research Council, 11421 Saskatchewan Drive, T6G 2M9,
Edmonton, Alberta, Canada.
2
Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto,
Nada-ku, 657-8501, Kobe, Japan.
3
Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.
4
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 5650871, Japan*misa.hayashida@nrc-cnrc.gc.ca
The higher order metaphase chromosome structure has been an enigma for over a century and several
different models have been presented based on results by various imaging techniques. Some of thedisagreements between methods have come from artifacts caused during sample preparation such as
staining and dehydration.
Therefore, we treated unstained barley chromosomes with ionic liquid to prevent dehydration.
Moreover, we observed chromosomes on a film with holes to prevent chromosomes from being flattenedwhen placed on the film, as show in Fig. 1. A chromosome which made a bridge over a hole (Fig. 2) was
mounted on a tomography holder [1], and observed its 3D structure using electron tomography. We foundthat there are periodic structures with 300-400 nm pitch along chromosome axis in barley chromosomes.
The pitch size is larger than the pitch observed in human chromosomes [2].
References:[1] R. Phengchat et. al., Micron, 126, 102736 (2019)[2] M. Hayashida et. al, Microscopy and Microanalysis (2021), 27, 149–155

Fig. 1 Illustrations of a chromosomes on acontinuous film and on a film with holes. The
chromosomes were flattened on the film andsometimes excessive ionic liquid remained in thesurface of the chromosomes when placed on acontinuous film.

35 | P a g e

Fig. 2. A TEM image of an unstained barley
chromosome and the line profiles, as indicated in
red in the left image. A chromosome which made abridge over a hole was observed.

In-situ STEM observation of Ni catalyst during dry methane reforming
山本 知一(Tomokazu Yamamoto)1*, 新村 光生(Mitsuki Shinmura)2, 松田 潤子(Junko Matsuda)3,
瓜田 幸幾(Koki Urita)4, 中越 修(Osamu Nakagoe)4, 松村 晶(Syo Matsumura)1, 2
1

Ultramicroscopy Research Center, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395,
Japan.
2
Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka,
Nishi-ku, Fukuoka 819-0395, Japan.
3International Research Center for Hydrogen Energy, Kyushu University, 744 Motooka, Nishi-ku,
Fukuoka 819-0395, Japan.
4
Graduate School of Engineering, Nagasaki University, 1–14 Bunkyo-machi, Nagasaki 852-8521,
Japan*
yamamoto@hvem.kyushu-u.ac.jp
Dry reforming of methane (DRM) with carbon dioxide (CO2) is has gained considerable researchattention for a method to produce a syngas mixture of carbon monoxide (CO) and hydrogen (H2), which
is a very important precursor for the production of a variety of valuable chemicals. Ni-based catalyst are
known as active catalyst for dry reforming of methane. The degradation of catalytic activity due to the
coking and sintering of catalysts remain a fundamental challenge. In this study, we investigated thegraphite formation on Ni nanoparticles under DRM gas condition using in-situ STEM observation.
In-situ STEM observation of Ni/MgO-Al2O3 catalyst was performed on a JEM-ARM200CF(JEOL) operated at 200 kV with a MEMS-type windowed gas-cell TEM holder system (Protochips
Atmosphere 210). A mixed gas: CH4: 50 vol%, CO2 vol%: 25, Ar: 25 vol% was flowed with 0.2 ml/min
at a gas pressure of 101 kPa. The flowed gas was also analyzed by QMS. Temperature was ramped from
300 ℃ to 900 ℃.
Fig.1 shows BF-STEM images of Ni nanoparticles under DRM condition. Graphite layer
formation was observed around 800 ℃. At this temperature, progress of DRM reaction was confirmed
by gas analysis (Fig. 2). Nanoparticle surfaces were changed to be flat during graphite layer formation.

Fig. 1. BF-STEM images of Ni nanoparticles under amixed gas (CH4: 50 vol%, CO2 vol%: 25, Ar: 25 vol%)flow (a) at 700 ℃ and (b) at 800 ℃.

36 | P a g e

Fig. 2. The QMS data vs time. The MS
intensity for each m/z channel was normalized
by the intensity of Ar balance gas.

STEM and EELS of Spontaneous Incommensurate van der Waals Heteroepitaxy
Hesham El-Sherif1,2, Stephen M. Jovanovic3, John Preston3, Nabil Bassim1,*
1
Materials Science and Engineering, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
2(current address) Rowland Institute, Harvard University, Cambridge, Massachusetts, 02138, USA.
3
Engineering Physics, McMaster University, Hamilton, Ontario, L8S 4L8 Canada.
*bassimn@mcmaster.ca
Heterogeneous integration of High-quality single-crystalline thin films may be achieved by insitu fabrication or lift-off technologies from compliant substrates with remote and van der Waals epitaxy
growth of semiconductors.[1] However, the quality of transferred semiconductor films depends on thequality and real-size of manually transferred two-dimensional (2D) materials, limiting the size of direct
large-area single-crystal films.
In this presentation, a one-step growth method will be introduced to fabricate thin films that areincommensurate to their substrate through a spontaneous van der Waals-like epitaxy.[2] In this relatively
low-temperate growth, a buffer layer of chalcogenide is spontaneously attached to the interface with aweak chemical interaction between a surface-reconstructed substrate and a 3D film. An epitaxial
relationship between the substrate and film is maintained across this interfacial layer. Moreover, nomismatch dislocations are observed at the interface, which allows high-quality single-crystal thin film
growth. This unique interface complexion allows for lift-off of films without first transferring a 2D
material onto their growth substrate for remoting epitaxy.
The presentation will focus on the fundamental interface understanding of cadmium telluride(CdTe) on sapphire system, fabricated via pulsed laser deposition at 300 °C.[2, 3] In Fig. 1, a mono-layerof chalcogenide (tellurium) at the interface is examined by various spectroscopic scanning transmission
electron microscopy (STEM) techniques, including low-loss and core loss electron energy-loss
spectroscopy (EELS) to reveal both the bonding and chemical composition at the interface.
Fig. 1. Understanding theinterface structure by Core-loss
EELS and STEM imaging. (aand b) STEM-HAADF and
STEM-BF images at theinterface showing CdTe in the(011), and (11) directions,
respectively. a monolayer
tellurium is resolved in an
EELS line scan in (c) and
EELS area map in (d). The
polarity of the film is Cd-polaras resolved by atomistic EELS
mapping in (e).

References[1] S-H Bae et al., Nature Nanotechnology 15 (2020), p. 272.
[2] SM Jovanovic et al., Small 16 (2020), p. e2004437.
[3] H El-Sherif et al., Microscopy and Microanalysis 26 (2020), S2, p. 3116

37 | P a g e

JSM MSC PHOTOS-November 15, 2021