Plenary lecture of the XX B-MRS Meeting given by Daniel Ugarte (UNICAMP) on September 27, 2022 at Foz do Iguaçu (Brazil).

1. FINE CHARACTERIZATION OF
NANOSCALE MATERIALS
BY TEM METHODS
Daniel M. Ugarte
Dept. Física Aplicada, Instituto de Física Gleb Wataghin-IFGW
Univ. Estadual de Campinas- UNICAMP, Campinas SP BRAZIL

2. Outline:
Introduction : Science progress: Ideas vs Tools
& new TEM paradigm (instrumentation)
TEM studies of Nanosystems:
Semiconductor NWs: defects & lattice distortion
Precession Electron Diffr. (PED): Screw disloc. +Torsion (Eshelby Twist)
Nanoparticles Characterization: beyond imaging
Pair Distrib. Function (PDF+PED)
Challenging aspects: an Unsolved Equation
Complex instrumentation & Human Resources Formation
Summary & …
Epilogue & aknowledgments

3. LEGO, danês ”leg godt”
“Play well!!!"
by Richard Feymann (December 29th 1959)
There's Plenty of Room at the Bottom
…arrange the atoms the way we want;
…greater range of possible properties
…possible by laws of physics. …
see individual atoms distinctly?
… importance of improving the electron microscope
not against the laws of diffraction of the electron.
The Nobel Prize
in Physics 1965
SCIENCE,
VOL 338, 14 DEC 2012
Achieving Great Scientific Progress
Thomas Kuhn (1922-1996) 100 Years
The Structure of Scientific Revolutions (1962)
“paradigm” (system of ideas “) discontinuous shift from one paradigm to other
Image and Logic (1997) Peter Galison
A different view of history…dominated by tools (nuclear physics, astronomy,...
XX century greatest scient. discovery: DNA (X-ray diffraction)
normal science ???? in Kuhn Picture

4. 2008 KAVLI PRIZE
in Nanoscience
Geometrical parameters
(Radius, Helicity)
conductors, insulator, semiconductor
no doping needed
Future ...Electronics (bottom-up)...
Nature 354, 56 (07 November 1991)
NW
Axis
Sumio Iijima
Discovery of Carbon nanotubes
Helicity!!!!! e-Diffraction:
Atomic resolution imaging
HRTEM seeing atoms (counting layers)
Semiconductor Metallic
EF
EF

5. Lagos et al, PRL 106, 055501 (2011)
Tamb ~ 300 K
Maureen Lagos
2012 CAPES Prize
PhD Physics
(Present:
Prof. MacMaster U.)
In-situ: Mechanical Elongation of atomic-szie Au wires (T dependence)
T ~ 150 K
Uncorrected TEM
+ Liq . N2 holder

6. TEM Paradigm Shifter: Aberration Correction
TEM is based on
magnetic lenses
Cylindrically Symm.
Magn. Lenses
are alway convergent
𝐶 → 𝜃
Strong Spherical aberration
Lorentz force
Multipolar Magnetic Lenses
S
S
N
N
N
S
F
B
v
Breaking
rotational symmetry
(limitation for ~ 50 ys)
Sub-ångström resolution
imaging and chemical analysis
using electron beams."
The Kavli Prize
in Nanoscience
2020
M. Haider, H. Rose, K. Urban, O. L. Krivanek
Kavli Prize Week Sept. 3-9 2022; Oslo & Trondheim, Norway.

7. Thomas, et al, CPL 631 (2015) 103
The rapidly changing face of TEM electron microscopy
Tomography
1D
Spectrum
3D
Data set
4D
Data set
Real Space
Shape, Atomic posit.
Spectroscopic
3D reconstruction
Reciprocal Space
3D reconstruction
Big Data
Machine learning
New Detectors
Quantitative Anal;
Spectr, Diffr & images
In-situ: T, Gazes,
liquids, etc.
Radiation Damage (Low dose)
Proteins << 1 e/Å2
STEM, maps 106 -109 e/Å2
Ptychography
(phase)
Electron Diffraction mapping (multiple Scattering)
Dynamical 𝒉𝒌𝒍 𝒉𝒌𝒍
𝟐
Wide
beam
STEM
Narrow beam
(4D STEM)

8. translating unknown structures or processes into
quantifiable, physically meaningful descriptors
and model representations.
Qualitative
Quantitative comparisons
(Residue)
Refinement
Model/ Simulations
Machine learning

9. TEM Characterization of NP:
Imaging most popular
LNNano, Campinas
Murilo Moreira
AuAg
Atomic Resolution
Electron
diffraction
Critical issues
Beam damage
Low Statistic
(few nanoparticles)
103 e-/Å2
104-106 e-/Å2
Low Dose approaches for
Structural Characterization
Alternatives to Imaging ??
Wide beam
Projection
Narrow beam
Scanning
HAADF
PRL 124, 106105(2020)
100 nm
6 e-/A2
beam  ~5 nm
Macpherson et al, Nature 294, 607 (2022)
Pt
perovskite
(extremely beam sensitive)
Cs0.05FA0.78MA0.17Pb(I0.83Br0.17)3
FA formamidinium
MA methylammonium
Direct Detection Camera
512x512 (medipix)

10. Electron Diffraction
Molecules Crystallography
(Cryo MicroED experiments)
Dimension < µm
Mass: Mx-Ray ~ Me x 104
Dose < 5 e-/Å2
Pharmaceutical Industry

11. Electron diff Pattern under “quase” Kinematical conditions
Precession Electron Diffraction- PED
Midgley & Eggeman IUCrJ 2 (2015) 126
Vincent & Midgley,
Ultramic.
53 (1994) 271.
Precession
de-Scan
Static Diff pattern
Hollow cone
Convent. Precess.
e-
Beam
y
z
x
Crystal orientation
(hkil)
along e-beam Direction
In Sample coord.
ND
PED
+nm Probe
+Fast Adq.
(SPED)
+ Pattern. Matching
(Kinem. patterns)
Post-Processing
Rauch, E. F. et al.. Microsc. Anal. 22, S5–S8 (2008).
ACOM
(Autom. Crystal orient. map)
Maps of Crystal
orientation and phases

12. Outline:
Introduction : generating novel ideas/concepts (NANO )
& new TEM paradigm (instrumentation)
TEM studies of Nanosystems:
Semiconductor NWs: defects & lattice distortion
Precession Electron Diffr.: Screw dislocation +Torsion (Eshelby Twist)
Nanoparticles Characterization: beyond imaging
Pair Distrib. Function (PDF+PED)
Challenging aspects: an Unsolved Equation
Complex instrumentation & Human Resources Formation
Summary & …
Epilogue & aknowledgments

13. Long and Short NWs
(~2 µm & > 4 µm )
[0-110] [2-1-10]
CBED
(1 nm probe)
InP NWs (Wurzite)
(0.14 ± 0.01 ) °/nm
30°Rot
Screw
dislocation
Frank
Model Growth
III-V Semiconductor Nanowires
CBE Reactor (Chem. Beam Epitaxy)- UNICAMP
Prof. Monica Cotta
Tizei et al.,
PRL 107, 195503 (2011)
P
In
BF-STEM:
periodical contrast bands
Crystal Torsion
Luiz Tizei
Present:
CNRS-Orsay FR
VLS-Au Catalyst.

14. Eshelby twist (50s- Classical Elasticity Theory)
Eshelby JD, J. App. Phys. 24, 176 (1953)
First observation 2008:
Branched NWs PbSe and PbS
Bierman MJ et al,
Science 320, 1060 (2008)
Screw
Dislocation
(Torque)
+
Free surface
(whisker or NW)
Double Helix Tower
Stockholm
Turning Torso, Malmö
Finite cylinder with
Axial Screw Dislocation)
𝟐
Torsion
B Burgers vector
R radius

15. ND= Crystal Normal
(hki 0)

e-beam
1) Torsion (Eshelby Twist)
2) Screw Dislocation
z
x
y
L
𝑁
𝑁
[0001] Crystal
Helicoidal Planes
Eshelby Twist (axial screw Dislocation)
InP NW (Wurtzite)
e-
Beam
y
z
x
PED yields
Crystal orientation
(hkil)
along
e-beam Direction
In Sample coord.)
ND
Disoreintation vs.
Reference Wire axis
P
In
High Spatial Resolution PED
(HSR-PED) or 4D STEM
Torsion
Screw
Dislocation
CM300-F 200 kV, ASTAR
prec. Angle 0.5 deg.,
Patterns 144x144 pixels
Dept. Mat. Sci. Metal.
Univ. Cambridge UK

16. 0001 -2110
-1010
Torsion rate |A|
(0.070±0.002) °/nm
3D NW shape
(hki0)
 3D determination of wire shape
VADF
f
3D
2D
300 nm
0
L
y
z
x
𝟐
Wire do not need to be perfectly oriented
(InP beam sensitive)
Ugarte et al, Nano Research 12, 939 (2019)
(hkil)

17. SPED 10 ms/pixel
Rotation 100 hz
PED pattern 144 X 144 pixels
~20000 pix
Highly distorted
Precession
de-Scan
Static pattern
100-1000 frames/s
Got linear response
Intensity-
Quantitative
ED Crystallography
1) Monocrystal
2) Pair Distrib.Function
PDF (+PED)
PED
Brazda et al, Science 364, 667 (2019)
Optical
recording
Phosporous
screen
e-Powder
Diffr.
Hoque et al,
J. Phys. Chem C 123.19894 (2019)
Correa et al,
ACS Applied Nanomat 4, 12541 (2021)
1) ACOM
(Autom. Crystal orient. map)
Post- processing 4D-STEM
Ihkl
-based
In-column camera
(CCD,CMOS, DDC)
2) Ring
Pattern

18. Prof. Dr. Arturo Ponce
Dept. Phys. Astron.
UTexas (Santo Antônio).
Jeol 2010F
TVIPS F416 detector CMOS
(16 bits, 4096x4096 bits).
Quantitative Comparison
Intensities Ihkil
(Experim. vs. Model)
Intensity
2)
V-ADF
20 nm
1) Template Matching
Diff. Pattern
Library
Cross-
correlation
Best fit
Kinematical
pattern
Refinement
3 Optimized Parameters
Torsion angle
C-axis Orientation
Scaling Intensity Factor
( ~80-100 s/pattern)
Correa et al, unpublished
ACOM (Autom. Crystal orient. map)
2-beam modeling
Dynam. Diffr. Approx.
Rauch et al, Symmetry 13, 1675 (2021)
Atomic scatt. factor Z
No Bragg angle dependence
Gjonnes, Ultram. 69,1 (1997) Oleynikov et al, Ultram. 107, 523 (2007)

19. Applied Ln to
Experim
Intensities
+
Cross Correl.
Template Matching
py4DSTEM (freeware)
Ophus et al, Microsc Microanal. 28. 390 (2022), .
Pyxem (freeware, Hyperspy)
McLaren et al, Microsc,&Microana, 26, 1110 (2020).
Cautaerts et al, Ultramicr.237, 113517 (2022)
Rauch et al,
Symmetry
13, 1675 (2021)
Expected: 0.017 ± 0.002 °/𝑛𝑚
Refinment ~60-80 s/pixel
R ~20 %
As expected using 2-beam model
Palatinus et al, Acta Cryst. B 71, 740 (2016)
Template Matching Refinement Ihkl
𝑅 =
∑ 𝐼 − 𝐼 𝐼
∑ 𝐼
𝒃
𝒄
𝒅
𝒂
y
z
x
X0.1
X0.15
Twist Rate Values
(0.006 ± 0.001) °/nm

20. Outline:
Introduction : generating novel ideas/concepts (NANO )
& new TEM paradigm (instrumentation)
TEM studies of Nanosystems:
Semiconductor NWs: defects & lattice distortion
Precession Electron Diffr.: Screw dislocation +Torsion (Eshelby Twist)
Nanoparticles Characterization: beyond imaging
Pair Distrib. Function (PDF+PED)
Challenging aspects: an Unsolved Equation
Complex instrumentation & Human Resources Formation
Summary & …
Epilogue & aknowledgments

21. Gaz
Coil AuAg
Cluster source
Cylindrical sputtering
1 3 5 [nm]
Counts
Mass-selected Cluster (Prof. Varlei)
Varlei Murilo (Ph.D)
Mach. Learning,
EDS-STEM
Leonardo (Ph.D.)
PED, ePDF
Diffraction
de Sá A. et al, J. Vac. Sci. Technol. B, 32, 061804 (2014)
Quantitative EDS on NP
(Big data, Mach. Learn.,, etc.)
( Inv Talk: V. Rodrigues,
Symp. L, X Micromat, Wedn. 28/09 , 14.30 )
Statistical validity of derived conclusion?
Low Dose approaches vs Imaging
(1-10 e/Å2 vs 106 e/Å2 )
Pair Distribution Function based on PED
Complex Polycyrst. Structure???
AuAg alloy NP
Titan Themis

22. i) e-Diffraction-based PDF
Abeykoon et al. (Billingue group), Z. Kristallogr. 227, 248 (2012)
SUePDF Software, Tran et al, J. Appl. Cryst. 50, 304 (2017)
Need of additional methods for quantitative and rapid
structural characterization of nanomaterials
Billingue & Levin, The Problem with determining atomic Structure at the Nanoscale, Science, 316, 561 (2007)
Pair Distribution Function (PDF)
Alternative for Crystallography in NANO
(peak broadening, etc.)
Billinge SJL. The nanostructure problem. Physics 3, 25 (2010)
Billinge SJL. The rise of the X-ray PDF method.
Phil. Trans. R. Soc. A 377: 20180413 (2019 )
Quantitative information may be
extracted from PDFs
using modeling.
JATOBÁ beamline high-energy, high-photon flux beam
focused on m size full X-ray scattering technique
+ PED
( 𝒉𝒌𝒍 𝒉𝒌𝒍
𝟐
)
Tutorial on
Powder X-ray Diffr.
for Characterizing
Nanoscale Materials
ACS Nano 13, 7359
(2019)
CdS spher. NP

23. Pair Distribution Function
- Suited for materials without long-range order
(Amorphous, Nanoparticles)
- Sensitive to NP domain structure
- Describes the distances between pairs of atoms
Start:
Powder Diffraction
(Reciprocal Space)
Reduced PDF
(Real Space)
Fourier T
to
Real Space
ePDFAllows
Mean Information
Minimal Sample Mass
(<ng)
Low Dose ( < 10 e-/Å2)
Quantitative
Crystallography
(Model vs Measurement)
2
Underneath the Bragg Peaks:
T. Egami and S.J.L. Billinge (2003)
Pair Distribution Function (PDF)
Mid-range
Short Range

24. SAED = 39% PED = 22%
Implementation of ePDF + PED
cryo-TEM holder (Gatan 915)
JEOL 2010F at 200 kV.
ASTAR Nanomegas
16-megapixel F416
CMOS camera (TVIPS)
U-Texas San Antonio
(Prof. A. Ponce)
Using Simple
Kinematical Modeling Software: SuePDF + DiffPy
Electron Diffraction:
Special Needs

25. Home-made Software (Python)
Aim: TEM specificity
- Astigmatism correction and pattern centering
- Azimuthal integration
- Background subtraction & normalization
- PDF calculation
- Powder diff. simulation: Debye Scattering Eq.
- Residue Calculation: Quantitative
6 nm
5 -10 nm
(Measured)
Astigm Corr.: F. Niekiel et al., Ultramic., 2017, 176, 161
DSE: B.D. Hall et al., Computer in Phys., 1991, 5, 414
Data Analysis
L. M. Correa
IFGW, Brazil.
Pair Distrib.Function (PDF) Based on PED
Composition : CAu ~70%
Mean Diameter : 6 nm
Mass : ≈ 2000 NPs or 4 fg
AuAg NP
PED 2.0º
- Not at all a fancy TEM
- TECNAI G2 200kV (LaB6),
(Univ. Fed. São Carlos)
- CCD Orius (Axial Cam!!!)
- RT , Dose = 10 e-/Å2
Cluster Source:
de Sá A. D. T., et
al.,
J. Vac. Sci. Technol.
B, 2014, 32, 061804

26. Data Processing (home-made)
1st Condition, Total Scatt. Conservation
2nd Condition, High Q
Equal
Background Substraction
Simultaneous Optimization
potential function (Q –n)
+
a-C Substrate (measured)
a-C
Simulation Powder Diff. Pattern (Debye Eq.)
Hall &, Monot, Computers in Physics 5, 414 (1991)
Non-periodic struct.
Disorder, etc.
( ) ( )
fcc
Dh Ico

27. Four different models
(a) fcc;
(b) single twinned fcc;
(c) Dh; decahedral,
bco-Body-Cent.-Orthorombic;
(d) Ih Icosahedral (rombohedral)
Why Dh is better?
A twin defect shows local order different from fcc or bco
Dh provides the correct balance
of local order and medium-range order
(different tetrhedra have
well established orientation relationship)
Optimization Results for SAED/PED
PED smaller residues
Quantitative comparison with
Kinematical diffraction modeling.
Only2 Parameters Optimization:
1) Debye-Waller 2) NP diameter

28. Complex Sample: Size distribution,
apparent agglomeration, polycrystalline??
Only 3 Parameters:
(1) Debye-Waller
Size Distribution ((2) mean and (3) width)
NP Structure
Decahedral
Considering Size Distribution
Structure Description (Residue):
Our Conventional TEM: 15%
Synchrotron: 12 to 17%
Correa et al., ACS Applied Nanomat. 2021, 4, 11, 12541
15%
20%
22%
23%
Longer r (bigger NP, stronger Dynamic. Effects)

29. Outline:
Introduction : generating novel ideas/concepts (NANO )
& new TEM paradigm (instrumentation)
TEM studies of Nanosystems:
Semiconductor NWs: defects & lattice distortion
Precession Electron Diffr.: Screw dislocation +Torsion (Eshelby Twist)
Nanoparticles Characterization: beyond imaging
Pair Distrib. Function (PDF+PED)
Challenging aspects: an Unsolved Equation
Complex instrumentation & Human Resources Formation
Summary & …
Epilogue & aknowledgments

30. “reproducibility crisis”, (U.S. National Academies of Science)
poor and incorrect materials data analysis in the literature.
analysis of XPS data in journals that emphasize next generation materials,
30% of the analyses are completely incorrect (Linford and Major, 2019).
proliferation of advanced analytical instruments seem to
have exceeded the world’s supply of expertise
to collect, interpret, and review the results obtained from them.
NOT “Black-box”
Push-botton Operators
need for reproducibility
For research results to have longevity and impact,
others must be able to replicate it, build on it
and take it in new directions
Nature, 608, 9 (4 August 2022)
Retraction Watch (Ivan Oransky)
evidence from surveys, studies and reports
~1 in 50 papers (~2%)
meet at least one criteria for retraction the
(Committee on Public. Ethics, non-profit collective in
Eastleigh, UK)
(actual rate 0.1%) 1/1000

31. A single method is rarely enough
electronic, magnetic, structural, thermal and many more …..
“Big” Facilities: Powerful “EXPENSIVE” machines
(ex. Synchrotron, state-of-the-art TEM, supercomputers,…)
“Small” science (universities)
individual-investigator laboratory
Dept, Ints., University
Materials characterization and the
evolution of material Sciences
CNPEM
Sirius
LMNANO
Tools OK
Higher impact....
?????
What about Ideas?
Human Resources
Formation
Starting research program,
questions, studying, testing,
routine work, Basic Infrastructure
Understanding
focusing ideas
Developing intuition
Consolidating
expertise/tech. ability
profound question!!
viable answer
time
Cutting-edge study
(ex. 10 hs TEM)
(Big Facility)
Bottom-up
1000
hs
.
TEM

32. Summary
- Electron nano-crystallography: PED (Tomography)
2022 new section of IUCrJ dedicated to e- crystallography
- Scanning Electron Diffraction (4D-STEM) strong growth
Strain nm-resolution (ACOM based on intesities Ihkl)
low dose 5-10 e/Å2 ,PED Patterns->Machine learning
- e-PDF+PED: Quantitative statistical information NP ensemble
sample (< pgr) Low dose (10 e/Å2) Low profile TEM!!!!
- Quantitative Chemical Composition inside few-nm NPs (EDS , ML)
Not presented ( Inv Talk: V. Rodrigues, Symp. L, X Micromat, Wedn. 14.30)
Funding (SPED NW):
Funding (ePDF): Advanced Microscopy Center at UTSA.
Dept.of Defense The Welch Foundation NSF
Brazil: CNPq, FAPESP, UNICAMP,CAPES
Epilogue & Aknowledgments: A few more slides

33. Start an Electron Microscopy Facility (90´s)
300kV
HRTEM
LV-SEM
FEG-SEM 200kV CTEM 200kV FEG-TEM
1999 2007-2009 Objectives (Since 1994)
1) To operate as an
“Actual” open
multi-user laboratory
(not Feudal, not sycophantic)
2) To train human resources
(Users/Students must operate the
microscope by themselves)
Best way to induce change
Education/ Teaching Young researchers
Still inside this endless battle!!
(Since 1994 .....
still many operational windmills.
“José Arana Varela” Award, XX B-MRS Meeting (SBPMat )
Annual SBPMat Award for Contribution to Braz. Materials Science

34. 2002 (J.A.Varela, E. Longo, E. Leite)
UNESP, UFSCar
FEG-TEM Expansion, Fapesp Sci. Dir.
1998 (Christian Colliex-
Lab. Phys. Sol., U. Paris Sud)
1994 (Prof. Cecilia Salvadori-USP)
Drive CPS-Caxambu MG-CPS
Quotation Sample Prep. Lab.
(Clatches periode)
Feb 2000 Nov 2000 Dec 1998, Daniela, Paulinho, Varlei
LNLS Directors: Cylon, Aldo, Ricardo Initial LME Team

35. 9th Nov 2020,
SBPMat Recognition
Placa gravada com os dizeres:
A Sociedade Brasileira de Pesquisa de Materiais (SBPMat)
homenageia a contribuição fundamental de Ricardo Rodrigues
para o êxito do desenvolvimento e implantação das
fontes brasileiras de luz síncrotron UVX e Sirius,
que colocaram o Brasil
na vanguarda mundial da pesquisa em materiais.