PREZENTACIJA OPREME

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PREZENTACIJA OPREME Institut za nuklearne
nauke Vinca Laboratorija za atomsku
fiziku
Nataa Bibic
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Skanirajuci elektronski mikroskop Philips SEM 501
Transmisioni elektronski mikroskop Philips EM 400
Van de Graaff akcelerator Proizvodjac je High
Voltage Engineering Corp. Cambridge-Massachusetts.
Koristi Van de Graaff-ov generator
500kV Jonski implanter Visoko-naponski terminal
ide od minimalnog napona 30-50 kV do
maksimalnog od 500 kV.
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Sredstva MNZS
TEM i SEM Donacija King College London
Februar
2004.god
Oktobar
Van de Graaff akcelerator
500kV Jonski implanter
Donacija Univerzitet Surrey, UK
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History First record of using glass lens for
magnification was by an Arabian from what is now
known as Iran, Alhazen, in the 10 and 11th
century. He contradicted Ptolemy's and Euclid's
theory of vision that objects are seen by rays of
light emanating from the eyes according to him
the rays originate in the object of vision and
not in the eye. Because of his extensive research
on vision, he has been considered by many as the
father of modern optics.

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15th century on - Studies done with glass
magnifiers to study objects in detail mostly as a
curiosity by non-scientists - Antonie van
Leeuwenhoek (linen draper) described three shapes
of bacterial cells using his simple, single lens
microscope (glass bead in metal holder).
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• 1935 - Max Knoll demonstrates the theory of the
  scanning electron microscope

1938 - First scanning electron microscope
produced by von Ardenne
von Ardenne
Knoll and Ruska 1986 Nobel Prize winners
1939 - Ruska and von Borries, working for Siemens
produce the first commercially available EM
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Resolution ? ½ ? Resolution is limited to
approx. 1/2 the wavelength of illuminating
source.
The greater the accelerating voltage the shorter
the l
Therefore, a 50,000 volt (50 kV) electron has a
wavelength of 0.0055nm and a 1MeV electron has a
wavelength of 0.00123nm!
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1 MeV 200 kV 100kV
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SEM
TEM
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SEM
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TEM
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Electron scattering from specimen
Resolution depends on spot size Typically a few
nanometers Topographic scan range order of mm X
mm X rays elemental analysis
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Electron Microscopy is usefully because we can
resolve very small things. SEM works with
reflected electrons yielding surface
information. TEM works with transmitted
electrons yielding information inside your
sample.
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Scanning Electron Microscope
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SEMs are patterned after Reflecting Light
Microscopes and yield similar information
Topography The surface features of an object or
"how it looks", its texture detectable features
limited to a few nanometers Morphology The
shape, size and arrangement of the particles
making up the object that are lying on the
surface of the sample or have been exposed by
grinding or chemical etching detectable
features limited to a few nanometers
Composition The elements and compounds the sample
is composed of and their relative ratios, in
areas 1 micrometer in diameter
Crystallographic Information The arrangement of
atoms in the specimen and their degree of order
only useful on single-crystal particles gt20
micrometers
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Laboratorija za atomsku fiziku
Philips SEM 501
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Transmission Electron MicroscopesWidely used
in materials science and biological
researchCapable of magnifying over a extremely
wide range (100 to gt1,000,000 x) Excellent
spatial resolution (better than 1 nm)Easy to
use and very reliable
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Disadvantages of TEMs Very expensive to own
and operate. Specimen preparation can be time
consuming and technically difficult.Specimen is
usually chemically fixed and epoxy embedded.
Specimen must be sliced into very, very thin
sections.the inside of an electron microscope
is a very hostile environment. It is under high
vacuum with zero humidity. Also, in the time it
takes to make an average 2 sec exposure of your
specimen with an 80 KeV beam, the amount of
energy the specimen receives is about 5 x109
rads, which is approximately equivalent to the
radiation delivered from a 10 megatonHydrogen
bomb exploding 30 meters away!
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TEMs are patterned after Transmission Light
Microscopes and will yield similar information.
Morphology The size, shape and arrangement of
the particles which make up the specimen as well
as their relationship to each other on the scale
of atomic diameters. Crystallographic
Information The arrangement of atoms in the
specimen and their degree of order, detection of
atomic-scale defects in areas a few nanometers in
diameter Compositional Information (if so
equipped) The elements and compounds the sample
is composed of and their relative ratios, in
areas a few nanometers in diameter
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100 keV e- l0.072 angstr. HRTEM sp. res. 0.2
nm
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A simplified ray diagram of a TEM consists of an
electron source, condenser lens with aperture,
specimen, objective lens with aperture,
projector lens and fluorescent screen.
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Transmission Electron Microscope
Basic premise of a TEM is to project a magnified
image of the specimen onto a fluorescent screen
where it can be viewed by the operator. The
image itself is the result of beam electrons
that are scattered by the specimen vs. those
that are not.
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In actuality a modern TEM consists of many more
components including a dual condenser system,
stigmators, deflector coils, and a combination
intermediate and dual projector lens.
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Total magnification in the TEM is a combination
of the magnification from the objective lens
times the magnification of the intermediate
lens times the magnification of the projector
lens. Each of which is capable of approximately
100X. Mob X Mint X Mproj Total Mag
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Growth of b-FeSi2 films via noble-gas
ion-beam mixing of Fe/Si bilayers
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Amorphous-iron disilicide A promising
semiconductor
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TEM IMAGES
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Laboratorija za atomsku fiziku
Philips EM 400
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Lokacija, Zaduenje
Korisnici
Laboratorije 040, 020, 030, 050,170 Univerzitet
u Novom Sadu
Laboratorija 040 N. Bibic
M.Popovic M.Novakovic S. Petrovic
TEM i SEM
Iskoricenost
Period od 1 godine i znacajna iskoritenost
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Potrebe
Dodatna oprema za pripremu uzoraka
SAMPLE PREPARATION
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Van de Graaff akcelerator High Voltage
Engineering Corp. Cambridge-Massachusetts. Van
de Graaff-ov generator
500kV Jonski implanter Visoko-naponski terminal
od minimalnog napona 30-50 kV do maksimalnog od
500 kV.
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In its passage through matter, an ion may
interact with

• THE ATOMIC ELECTRONS
• and/or
• THE ATOMIC NUCLEI

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Principles of ion beam analysis
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RBS
In RBS, a beam of mono-energetic (1-2 MeV)
collimated light ions (H, He) impinges
(usually at normal incidence) on a target and
the number and energy of particles that are
scattered backwards at a certain angle are
monitored to obtain information about the
composition of the target (host species and
impurities) as a function of depth.
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RBS
Kinematic factor, Mass identification Energy
loss, Depth scale Scattering cross
sections, Composition, (quantitative)

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KINEMATIC FACTOR
E can be derived from the principle of
conservation of energy and momentum, and is
given by (in laboratory frame of reference)
The multiplication factor of Eo on the right hand
side of the equation is often referred to as the
kinematic factor and is denoted by k. For M/m gt
1, k is a slow-varying function of ?, having the
maximum value of 1 at ? 0 and the minimum
value at ? 180o. For M/m 1, the value of k
is zero beyond 90o.
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DIFFERENTIAL SCATTERING CROSS SECTION
The theoretical differential cross section for a
given scattering angle is given by
The higher order terms are usually negligible for
Mgtm and the differential cross section can be
expressed in the following form, which has the
unit of mb/sr (millibarn per steradian) when MeV
is used as the unit for Eo
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A ??QNt
A- ukupan broj detektovanih cestica ?- efikasni
presek rasejanja ?- prostorni ugao Q- ukupan broj
upadnih cestica N- kocentracija atoma mete t-
debljina
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Thickness 200A
Pt
Co
Thickness 1000A
Pt
Co
Co
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Schematic view of the ion beam mixing experiments
Ar, Xe and Au ions
Fluence 1x1015-2x1016 ions/cm2
Ion energy 100-700 keV

RBS, XRD, and CEMS analyses of solid solution
and compound formation
Thickness 30-90nm
Fe
FexSiy
Si
Liquid nitrogen room temperature
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RBS spectra (a) Fe and Si concentration profiles
(b) of Fe/Si bilayers
irradiated with 1x1015 - 2x1016 Xe ions/cm2 at
250 keV
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The quantitative
information of the redistribution
of the components across the
interface Interface variance of the
mixed Fe/Si bilayer ??2, after RT irradiation,
as a function of ion
fluence ? (a) Ar and (b) Xe
??2/? 1.3 0.2 nm4
k (mixing rates)
??2/? 4.8 0.5 nm4
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Interface broadening variance ??2 versus ion
fluence ? for Fe/Si bilayers irradiated with a
100 keV Ar ions, 250 keV Xe and 700 keV
Xe2, and 400 keV Au

• a) linear dependece
• b) athermal regime
• c) influence of ion mass

The deduced mixing rates are inserted
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RBS spectra (a) Fe and Si concentration profiles
(b) of 57Fe/Si bilayers
irradiated with 0.6x1017 - 2x1017 N2 ions/cm2 at
22 keV
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Van de Graaff akcelerator
500kV Jonski implanter
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Analizatorski magnet, 500kV implanter
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Skretni magnet VdG
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RBS linija
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Van de Graaff
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Blok ema VdG generatora
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Van de Graaff akceleratorska cev
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Lokacija, Zaduenje
Korisnici
Laboratorija 040 N. Bibic
Istraivanja u oblasti fizike cvrstog stanja i
materijala
Van de Graaff akcelerator
500kV Jonski implanter
Iskoricenost
Rad u kontinuitetu od 7h, 1 uzorak 15-30 min.