1.1 - Introduction to transmission electron microscopy (TEM)
Summary
TLDRIn this introductory course on Transmission Electron Microscopy (TEM), Professor Calvin Shear from Texas A&M University offers a comprehensive overview of TEM's principles and applications. He shares his academic background and research experience using TEM in various studies, including materials characterization and phase transformations. The course covers five sections: basics, diffraction, imaging, spectroscopy, and related TEM techniques. It utilizes several key textbooks and resources, emphasizing the structural and chemical information TEM provides. The course also highlights advanced TEM techniques like aberration correction and scanning transmission electron microscopy (STEM).
Takeaways
- ๐ค The course is an introduction to Transmission Electron Microscopy (TEM), taught by Calvin Shear, an assistant professor in the Department of Material Science and Engineering at Texas A&M University.
- ๐ Calvin Shear has a diverse academic background, with undergraduate studies in biomedical engineering and finance at the University of Sydney, and a PhD in mechanical engineering focusing on high-strength low-alloy steel.
- ๐ฌ TEM and Atom Probe were key tools in his research during his PhD to study solute clusters, and post-PhD, he worked at Johns Hopkins University, using TEM to study deformation mechanisms in boron carbide and magnesium.
- ๐งโ๐ซ The course will cover a wide range of topics, including electron scattering, instrumentation, sample preparation, diffraction, imaging, spectroscopy, and related TEM techniques.
- ๐ The main textbook for the course is 'Transmission Electron Microscopy' by Williams and Carter, supported by other resources like 'Microstructural Characterization of Materials' and 'Aberration-Corrected Imaging'.
- ๐ผ๏ธ Five main sections of the course include basics, diffraction, imaging, spectroscopy, and TEM-related techniques, with detailed discussions on each topic.
- ๐ก In the basics, the course will explore electron scattering, electron sources, and lenses, as well as sample preparation methods like electro-polishing and lift-out for specific samples.
- ๐ The diffraction section covers parallel beam diffraction, Kikuchi diffraction, and convergent beam electron diffraction, explaining how each provides different visual patterns (spots, lines, disks).
- ๐ Imaging will delve into three types of contrast (mass-thickness, diffraction, and phase contrast) to analyze different materials and samples at atomic resolution.
- ๐ The spectroscopy section introduces EDS and EELS techniques, enabling students to gather both chemical and bonding information about materials, particularly when combined with scanning TEM and aberration correction.
Q & A
What is the main focus of this Transmission Electron Microscopy (TEM) class?
-The main focus of this class is to provide an overview of Transmission Electron Microscopy (TEM) and its applications in material science.
Who is the instructor of the class, and what is his academic background?
-The instructor is Calvin Shear, an assistant professor in the Department of Material Science and Engineering at Texas A&M University. He has a background in biomedical engineering and finance from the University of Sydney and a PhD in mechanical engineering.
What technique is emphasized in this course that is specific to Texas A&M University?
-The course emphasizes the use of a special TEM technique called precession electron diffraction, which is used to study the formation and phase transformations in materials.
Which textbook is primarily used for this course, and what is its significance?
-The textbook used is 'Transmission Electron Microscopy' by Williams and Carter, often referred to as the 'Bible' for TEM due to its comprehensive coverage of the subject.
What are the five main sections of the TEM course as outlined by the instructor?
-The five main sections of the course are basics, diffraction, imaging, spectroscopy, and TEM-related techniques.
What are the three types of contrast discussed in the imaging section of the course?
-The three types of contrast discussed are mass-thickness contrast, diffraction contrast, and phase contrast. These contrasts help in imaging biological samples, crystal defects, and atomic structures, respectively.
What are the two spectroscopy techniques covered in the course, and what information do they provide?
-The two spectroscopy techniques are Energy Dispersive X-ray Spectroscopy (EDS) and Electron Energy Loss Spectroscopy (EELS). EDS provides chemical information, while EELS offers both chemical and chemical bonding information.
How does the instructor describe the impact of aberration correction in TEM imaging?
-The instructor explains that aberration correction in TEM significantly improves image quality. He shows an example where an aberration-corrected image reveals more detailed atomic structures compared to a non-corrected image.
What is the significance of combining EDS and EELS with STEM in the context of this course?
-Combining EDS and EELS with Scanning Transmission Electron Microscopy (STEM) allows for the chemical analysis of individual atomic columns, providing highly detailed structural and chemical information.
What is the expected outcome for students by the end of this TEM course?
-By the end of the course, students are expected to have a good understanding of how TEM works and how it can be applied to research in material science.
Outlines
๐ Introduction to Transmission Electron Microscopy (TEM)
In this introductory section, Professor Calvin Shear welcomes the audience to his course on Transmission Electron Microscopy (TEM). He provides an overview of his background, including his undergraduate studies in biomedical engineering and finance at the University of Sydney, followed by a PhD in mechanical engineering. His research involved using TEM and atom probe techniques to study high-strength alloy steels. Afterward, he joined Johns Hopkins University to investigate deformation mechanisms in materials like boron carbide and magnesium, eventually becoming a microscopy faculty member at Texas A&M University, specializing in advanced TEM techniques.
๐ Course Materials and Structure
This section outlines the primary textbook for the course, *Transmission Electron Microscopy* by Williams and Carter, which is considered essential for TEM studies. Additional resources include *Microstructural Characterization of Materials* by Brendan and Kaplan and *Introduction to Scanning Electron Microscopy*. The course will cover five major sections, each corresponding to a YouTube playlist: basics, diffraction, imaging, spectroscopy, and advanced TEM techniques. Each section will dive deep into the various methods and topics in TEM, preparing students for advanced research in material science.
๐ฌ Basics of Electron Scattering and Instrumentation
In the basics section of the course, Professor Shear will discuss electron scattering and the fundamental components of a TEM instrument, including electron sources, lenses, and the importance of sample preparation. The two examples of sample preparation methods include electro-polishing for metal samples and site-specific lift-out techniques. This foundational knowledge sets the stage for further exploration of how TEM works and how samples are prepared for analysis.
๐ Electron Diffraction Techniques
This paragraph introduces electron diffraction, explaining how and why diffraction occurs within a TEM. Various diffraction techniques are explored, such as parallel beam diffraction, Kikuchi diffraction, and convergent beam electron diffraction (CBED). Each method produces different visual outcomesโspots, lines, or disksโthat help researchers analyze material structures. These diffraction techniques are essential for understanding crystallographic information.
๐ Imaging and Contrast in TEM
In this part of the course, different types of imaging and contrast mechanisms in TEM are discussed. Professor Shear explains three types of contrastโmass thickness contrast, diffraction contrast, and phase contrastโeach used to visualize different material features, such as biological samples or crystallographic defects. Examples include high-resolution TEM images showing atomic-level details like nano twins in boron carbide, with applications in understanding material deformation and structure.
๐ Spectroscopy Techniques in TEM
This section covers spectroscopy techniques that provide chemical information about materials. Two key methodsโEnergy Dispersive X-ray Spectroscopy (EDS) and Electron Energy Loss Spectroscopy (EELS)โare introduced. EDS helps in identifying chemical compositions, while EELS offers insights into chemical bonding. Examples include comparing EELS spectra for diamond, carbon 60, and graphite, showing how these techniques can reveal subtle material differences at the atomic level.
๐งช Advanced TEM Techniques and Applications
The final section delves into advanced TEM techniques, including Scanning Transmission Electron Microscopy (STEM) and precession electron diffraction, which can be compared to Electron Backscatter Diffraction (EBSD). Aberration-corrected TEM is highlighted as a powerful tool for achieving high-resolution images, with examples showing the dramatic improvements in image clarity when aberration is corrected. The course aims to equip students with the skills to understand and apply these advanced techniques in their research.
Mindmap
Keywords
๐กTransmission Electron Microscopy (TEM)
๐กElectron Diffraction
๐กSample Preparation
๐กMass Thickness Contrast
๐กDiffraction Contrast
๐กSpectroscopy
๐กAberration Correction
๐กPrecession Electron Diffraction
๐กHigh-Resolution TEM (HRTEM)
๐กEnergy Dispersive X-ray Spectroscopy (EDS)
Highlights
Introduction to Transmission Electron Microscopy (TEM) by Calvin Shear, Assistant Professor at Texas A&M University.
Calvin Shear's academic background includes a Bachelorโs degree in Biomedical Engineering and Finance from the University of Sydney, and a PhD in Mechanical Engineering.
Shearโs PhD research utilized both TEM and Atom Probe to study solar clusters in high-strength, low-alloy steel.
After his PhD, Shear joined Johns Hopkins University, where he used TEM to study deformation mechanisms in boron carbide and magnesium.
In 2018, Shear became part of Texas A&M Universityโs Department of Material Science and Engineering, focusing on microscopy.
At Texas A&M, Shear uses a specialized TEM technique called Precession Electron Diffraction to study material formation and phase transformation.
The courseโs primary textbook is 'Transmission Electron Microscopy' by Williams and Carter, commonly referred to as the 'Bible' for TEM.
Additional resources include 'Microstructural Characterization of Materials' by Brandon and Kaplan, and 'Aberration-Corrected Imaging in Transmission Electron Microscopy' by Erni.
The TEM course is divided into five sections: basics, diffraction, imaging, spectroscopy, and TEM-related techniques.
The basics section covers electron scattering, electron sources, lenses, and sample preparation techniques like electro-polishing and lift-out methods.
Electron diffraction is explained with various techniques, including Parallel Beam Diffraction (spots), Kikuchi Diffraction (lines), and Converging Beam Electron Diffraction (disks).
The course emphasizes three types of contrast in TEM imaging: mass-thickness contrast, diffraction contrast, and phase contrast.
Spectroscopy section focuses on Energy Dispersive X-ray Spectroscopy (EDS) and Electron Energy Loss Spectroscopy (EELS), providing chemical and bonding information.
Advanced TEM techniques include Scanning Transmission Electron Microscopy (STEM), Precession Electron Diffraction, and Aberration-Corrected TEM.
By the end of the course, students are expected to understand how TEM works and how it can enhance their research.
Transcripts
howdy welcome to my introduction to the
transmission electron microscopy class
my name is Calvin shear and I am an
assistant professor in the Department of
material science and engineering at
Texas A&M University
the aim of this online class is to give
you an overview of what is TEM and what
he young can do or just use one slide to
share with you my background I did my
undergraduate studies at University of
Sydney in Australia my bachelor degrees
from biomedical engineering believe it
or not I also have a degree in finance
aizen State at the University of Sydney
and completed my PhD in the Department
of Mechanical Engineering my PhD
advisors are professors Judy carne and
the Simon ringer during my PhD are used
both TEM and Adam probe to study the
solar clusters in a high strength low
alloy steel after my PhD a joint
professor Kevin Henkes group at Johns
Hopkins University
I was the in-house TEM person and using
TEM as at all to study the defamation
mechanisms in boron carbide and a
magnesium in 2018 I joined the
department of material science and
engineering at Texas A&M as a microscopy
faculty at Texas A&M we use a special TM
technique called precession electron
diffraction to study the formation and
the phase transformation in materials
the textbook were going to use for this
course is transmission electron
microscopy by Williams and Carter this
is also referred as the Bible for TEM to
complement the Williams and Carter books
we will also use the resources from a
few other books the first one is the
micro structural characterization of
materials by Brendan and Kaplan a few
chapters of the book are devoted to TM
and a TM based techniques if you want to
have a quick read about TM it's a very
nice book we will also use the
information from introduction to
scanning electron microscopy or stem the
last one is the aberration corrected
imaging inference electron microscopy by
Ernie there will be five sections of
this TM course all five playlists on
YouTube
there will be on the basics diffraction
imaging spectroscopy and other TM
related techniques in basics we'll start
by talking about the electron scattering
in TEM the were moved to the
instrumentation talking about the
electron sources lenses etc we will also
talk about sample preparation in these
two examples specifically the one on the
left is electro polishing to prepare
metal samples the one on the right is a
lift out for site-specific samples the
second section is on electron
diffraction both talked about why and
how diffraction happens in TEM we will
then discuss the parallel beam
diffraction and indexing Kikuchi
diffraction and convergence beam
diffraction in parallel beam diffraction
you see spots in Kikuchi diffraction you
see lines in converging beam electron
diffraction you see disks in the third
section of this course or discuss
imaging and is the origin of contrast
there are three types of contrast mass
thickness contrast diffraction contrast
and face contrast the mass thickness
contrast is used to image stained
biological samples the example here
shows the mitochondria in a Cell
diffraction contrast is used to image
crystal graphic defects such as
dislocations and stacking faults the
examples showing here are from my own
research with Professor Kevin honker the
dark lines in the left figure and the
bright lines in the right figure artists
locations the reason we can see the
atomic level information in high-res DM
images is due to the face contrast again
this example was from my own research
with Professor Kevin honker showing the
nano twins in a boring car by sample the
fourth section is spectroscopy imaging
and the diffraction will give you the
structural information spectroscopy will
give you the chemical information the
two spectroscopy techniques going to
discuss our energy dispersive x-ray
spectroscopy EDS and electron energy
loss spectroscopy eels using EDS you can
get the chemical information using eels
in addition to the chemical information
you can also get the chemical bonding
information from this example here you
can see the eros spectrum of diamond
looks very different from carbon 60 and
graphite combining EDS and eels with
stem using an aberration corrected TEM
you can get the chemical information of
individual atomic columns the figure
here is from Cornell University and it's
just striking
in the last section we'll introduce some
tea and related techniques the first one
is the scanning transmission electron
microscopy stem these stem images were
acquired by my student Hershey
highlighting the nano precipitates in a
shape memory alloy we will also talk
about the precession electron
diffraction this technique can be
somewhat viewed as EB SD inside TEM
lastly we'll talk about is the
aberration corrected TEM the micrographs
were taken from the Williams and Carter
book the image on the left has no
aberration correction while the one on
the right is with the aberration
correction you can see the difference
straight away at the end of this course
I hope you will be able to develop a
good understanding on how TM works and
what TM can do to help your research in
the next video we'll talk about why we
use electron inside TEM and the
resolution of TEM
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