5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.
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Transcript of 5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.
![Page 1: 5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.](https://reader036.fdocuments.us/reader036/viewer/2022062721/56649f265503460f94c3d9fc/html5/thumbnails/1.jpg)
![Page 2: 5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.](https://reader036.fdocuments.us/reader036/viewer/2022062721/56649f265503460f94c3d9fc/html5/thumbnails/2.jpg)
![Page 3: 5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.](https://reader036.fdocuments.us/reader036/viewer/2022062721/56649f265503460f94c3d9fc/html5/thumbnails/3.jpg)
5 kV = 0.5 nm
![Page 4: 5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.](https://reader036.fdocuments.us/reader036/viewer/2022062721/56649f265503460f94c3d9fc/html5/thumbnails/4.jpg)
Ato
mic
res
olut
ion
TE
M im
age
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EBPG (Electron beam pattern generator)
100 kV = 0.12 nm
![Page 6: 5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.](https://reader036.fdocuments.us/reader036/viewer/2022062721/56649f265503460f94c3d9fc/html5/thumbnails/6.jpg)
SNOM
To locate single molecules:Optical microscopy:-fluorescence (labeling)-particle tagging(-electron microscopy)
![Page 7: 5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.](https://reader036.fdocuments.us/reader036/viewer/2022062721/56649f265503460f94c3d9fc/html5/thumbnails/7.jpg)
Piezoelectric (Voltage – Displacement)
Precise tip control is achieved with Piezoelectrics
Displacement accurate to ± .05 Å
PZT = (Pb,Zr)TiO3
![Page 8: 5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.](https://reader036.fdocuments.us/reader036/viewer/2022062721/56649f265503460f94c3d9fc/html5/thumbnails/8.jpg)
Basic Principles of STM
Electrons tunnel between the tip and sample, a small current I is generated (10 pA to 1 nA).
I proportional to e-2κd, I decreases by a factor of 10 when d is increased by 1 Å.
d ~ 6 Å Bias voltage:mV – V range
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Copper Surface
Silicon
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Silicium-oppervlak met stappen
(Bron: Sandia Nat.Labs.)
Si(100)
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Two Modes of Scanning
Constant Height Mode
Constant Current Mode
Usually, constant current mode is superior.
![Page 12: 5 kV = 0.5 nm Atomic resolution TEM image EBPG (Electron beam pattern generator) 100 kV = 0.12 nm.](https://reader036.fdocuments.us/reader036/viewer/2022062721/56649f265503460f94c3d9fc/html5/thumbnails/12.jpg)
Instrumental Design Continued
TipsCut platinum – iridium wires
Tungsten wire electrochemically etched
Tungsten sharpened with ion milling
Best tips have a point a few hundred nm wide
Vibration Control
Coiled spring suspension with magnetic damping
Stacked metal plates with dampers between them
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Interpreting STM Images
Hydrogen on Gadolinium
“Topography” model good for large scale images, but not for the atomic level.
Electron charge density model more accurate for atomic level images.
Best model requires complex quantum mechanical considerations
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Atomic Force microscope(Scanning Force Microscope)
PiezoElectric
positioner
Feedbackelectronics
Laser diodeDeflection detector
Flexible cantilever
Probe tip
display
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AFM Tip
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y
z
l
L
ylL
z 3 l ~ 100m
L ~ 3 cm
z ~ 1000 y !!!
Detection: beam deflection
Optical lever amplification
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Scanning modes
Constant height Constant force
Contact mode Tapping mode
High friction No friction forces
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Resolution: scanning probe microscope
object tip geometry image
Tip convolution is not linear: results DO NOT add upResolution is depends on tip AND sample
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Imaging and manipulationof Carbon nanotubes
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Millipede 1024 tips