scanning probe microscopy.pptx

8/20/2019 Scanning Probe Microscopy.pptx

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OUTLINE

Background and History

Scanning Probe Microscopy

comparison

Types Scanning Tunneling Microscopy

Atomic Force Microscope (AFM)

-Advantage

-isadvantage -Application

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Scanning Probe Microscopy• Scanning probe microscopy (SPM is a ne! branc" o#

$icroscopy %

• An i$age o# &"e s'r#ace is ob&aine by $o)ing &"e probe in a

ras&er scan o# &"e speci$en* +ine by +ine* an recoring &"e

s'r#ace i$ages%• T"e posi&ion o# &"e &ip !i&" respec& &o &"e s'r#ace $'s& be )ery

acc'ra&e+y con&ro++e (&o !i&"in abo'& ,%- . by $o)ing ei&"er &"e

s'r#ace or &"e &ip%

• I& is possib+e &o acc'ra&e+y con&ro+ &"e re+a&i)e posi&ions o# &ip

an s'r#ace by ens'ring goo )ibra&iona+ iso+a&ion o# &"e

$icroscope an 'sing sensi&i)e pie/oe+ec&ric posi&ioning e)ice%

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http://en.wikipedia.org/wiki/Microscopyhttp://en.wikipedia.org/wiki/Raster_scanhttp://en.wikipedia.org/wiki/Raster_scanhttp://en.wikipedia.org/wiki/Microscopy


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Types of scanning probe microscopy

A0M* a&o$ic #orce $icroscopy

E0M* e+ec&ros&a&ic #orce $icroscope

0MM* #orce $o'+a&ion $icroscopy

M0M* $agne&ic #orce $icroscopySTM* scanning &'nne+ing $icroscopy

S1M* scanning )o+&age $icroscopy

S2PM* scanning 2a++ probe $icroscopy

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http://en.wikipedia.org/wiki/Atomic_force_microscopyhttp://en.wikipedia.org/wiki/Electrostatic_force_microscopehttp://en.wikipedia.org/w/index.php?title=Force_modulation_microscopy&action=edithttp://en.wikipedia.org/wiki/Magnetic_force_microscopyhttp://en.wikipedia.org/wiki/Scanning_tunneling_microscopyhttp://en.wikipedia.org/wiki/Scanning_voltage_microscopyhttp://en.wikipedia.org/wiki/Scanning_Hall_probe_microscopyhttp://en.wikipedia.org/wiki/Scanning_Hall_probe_microscopyhttp://en.wikipedia.org/wiki/Scanning_voltage_microscopyhttp://en.wikipedia.org/wiki/Scanning_tunneling_microscopyhttp://en.wikipedia.org/wiki/Magnetic_force_microscopyhttp://en.wikipedia.org/w/index.php?title=Force_modulation_microscopy&action=edithttp://en.wikipedia.org/wiki/Electrostatic_force_microscopehttp://en.wikipedia.org/wiki/Atomic_force_microscopy


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Scanning T'nne+ing Microscopy (STM

T"e STM is an $icroscope &"a& 'ses a sing+e a&o$ &ip&o a&&ain a&o$ic reso+'&ion%

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An e!tremely "ine conducting probe is #eld

about an atom$s diameter "rom t#e sample%

&lectrons tunnel bet'een t#e sur"ace and t#e tip

producing an electrical signal%

#ile it slo'ly scans across t#e sur"ace

t#e tip is raised and lo'ered in order to keep

t#e signal constant and maintain t#e distance%

T#is enables it to "ollo' even t#e smallest

details o" t#e sur"ace it is scanning.

Basic opera&ion10


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STM Moes o# Opera&ion

Cons&an& C'rren&Main&ain a cons&an& &'nne+ingc'rren& by a3's&ing &"e separa&ion

Cons&an& 2eig"&Main&ain a cons&an& "eig"& an$eas're &"e c'rren& c"ange

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Prob+e$s an So+'&ions• Bringing &"e &ip c+ose &o &"e s'r#ace an scanning &"e s'r#ace

Feedback Servo oops• 4eeping &"e &ip c+ose &o &"e s'r#ace

!onverse "ie#oe$ec%rici%y

• Crea&ing a )ery #ine &ip

&$ec%ro'c(emica$ e%c(ing• 0orces be&!een &ip an sa$p+e

)eg$igib$e in mos% cases• Mec"anica+ )ibra&ions an aco's&ic noise

Sof% s*spension of %(e microscope +i%(in an *$%ra

(ig( vac**m c(amber ,10-11 Torr)

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STM I$ages

5enon on Nic6e+ (--,Nickel (110)

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-%omic Force .icroscope ,-F./

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n%rod*c%ion

• Mos& !ie+y 'se branc" o# scanning probe $icroscopy• Opera&es by $eas'ring &"e in&erac&ion #orce be&!een &"e

&ip an sa$p+e%• A0M 7 is &"e )an er 8aa+s #orce be&!een &"e &ip an &"e

s'r#ace9 &"is $ay be ei&"er &"e s"or& range rep'+si)e #orce(in con&ac&7$oe or &"e +onger range a&&rac&i)e #orce (innon7con&ac& $oe%

8or6ing concep& o# A0M

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A0M

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-% Laser:% Mirror;% P"o&oe&ec&or

% Sa$p+e?% Probe@% Can&i+e)er


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A0M OPERATION

• An a&o$ica++y s"arp &ip is scanne o)er a s'r#ace !i&"#eebac6 $ec"anis$s &o $ain&ain &"e &ip a& a cons&an&#orce (&o ob&ain "eig"& in#or$a&ion* or "eig"& (&o ob&ain#orce in#or$a&ion abo)e &"e sa$p+e%

• Tips are &ypica++y $ae #ro$ Si;N


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asic se%'*p of an -F.

T"e abi+i&y o# an A0M &o ac"ie)e near a&o$ic sca+e reso+'&ion epens on &"e

&"ree essen&ia+ co$ponen&s a can&i+e)er !i&" a s"arp &ip*

a scanner &"a& con&ro+s &"e x 7y 7z posi&ion* an

&"e #eebac6 con&ro+ an +oop%

Cantiliever with a sharp tip% T"e s&i##ness o# &"e can&i+e)er nees &o be +ess%

• T"e &ip s"o'+ "a)e a rai's o# c'r)a&'re +ess &"an :,7=, n$ (s$a++er is

be&&er a cone ang+e be&!een -,7:, egrees%

Scanner T"e $o)e$en& o# &"e &ip or sa$p+e in &"e x * y * an z 7irec&ions is

con&ro++e by a pie/o7e+ec&ric &'be scanner* si$i+ar &o &"ose 'se in STM%

• 0or &ypica+ A0M scanners* &"e $ai$'$ ranges #or are @, $$ @, $$ in &"e

x 7y p+ane an = $$ #or &"e z 7irec&ion%

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Feedback control. The forces that are exerted

between the tip and the sample are measured by the

amount of bending (or deflection) of the cantilever.

By calculating the difference signal in the photodiode

quadrants, the amount of deflection can be correlated

with a height .

Because the cantilever obeys Hooke's Law for small

displacements, the interaction force between the tip

and the sample can be determined.

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A0M Opera&ion Moes

Con&ac& Moe• Tip re$ains in &"e rep'+si)e regi$e o# &"e in&er7$o+ec'+ar #orce

c'r)e

Tapping Moe• Tip is osci++a&e a& a "ig" #re'ency• De#+ec&ions in &"e osci++a&ions

are obser)e

Non7Con&ac& Moe• Tip is osci++a&e o'&sie

o# &"e rep'+si)e regi$e

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-pp$ica%ions

T"e A0M is 'se#'+ #or ob&aining &"ree7i$ensiona+ &opograp"ic

in#or$a&ion o# ins'+a&ing an con'c&ing s&r'c&'res !i&" +a&era+

reso+'&ion o!n &o -%= n$ an )er&ica+ reso+'&ion o!n &o ,%,= n$%

T"ese sa$p+es inc+'e c+'s&ers o# a&o$s an $o+ec'+es* ini)i'a+

$acro$o+ec'+es* an bio+ogica+ species (ce++s* DNA* pro&eins%

Si$i+ar &o STM opera&ion* &"e A0M can opera&e in gas* a$bien&* an

#+'i en)iron$en&s an can $eas're p"ysica+ proper&ies inc+'ing

e+as&ici&y* "arness* #ric&ion an c"e$ica+ #'nc&iona+i&y%

Me&a+s &oo+ing s&'ies* ro'g"ness $eas're$en&s* corrosion s&'ies%%%

So+i po!er ca&a+ys&s aggrega&e s&r'c&'ra+ e&er$ina&ion

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-dvan%ages

T"e A0M "as se)era+ a)an&ages o)er &"e scanninge+ec&ron $icroscope (SEM%

Un+i6e &"e e+ec&ron $icroscope !"ic" pro)ies a &!o7i$ensiona+ pro3ec&ion or a &!o7i$ensiona+ i$age o# asa$p+e* &"e A0M pro)ies a &r'e &"ree7i$ensiona+ s'r#acepro#i+e%

Ai&iona++y* sa$p+es )ie!e by A0M o no& re'ire anyspecia+ &rea&$en&s (s'c" as $e&a+carbon coa&ings &"a& !o'+irre)ersib+y c"ange or a$age &"e sa$p+e% T"is $a6es i& possib+e &o s&'y bio+ogica+ $acro$o+ec'+es

an e)en +i)ing organis$s% In princip+e* A0M can pro)ie "ig"er reso+'&ion &"an SEM% I&"as been s"o!n &o gi)e &r'e a&o$ic reso+'&ion in '+&ra7"ig")ac''$ (U21%

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http://en.wikipedia.org/wiki/Electron_microscopehttp://en.wikipedia.org/wiki/Electron_microscope


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A0M I$ages

-, F$ scan Tapping Moe i$age o# a CD (+e#& an a D1D (rig"& s'r#ace isc

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Re#erences

• G% Binnig an 2% Ro"rer% Scanning T'nne+ingMicroscopy* IBM H Res% De)e+op%* ;,;==* -@>%

• G% Binnig* 2% Ro"rer* JScanning T'nne+ing Microscopy 70ro$ Bir&" &o Ao+escenceK* Nobe+ +ec&'re* Dece$ber @*-@$

• 8i6ipeia* JScanning T'nne+ing MicroscopeK*"&&pen%!i6ipeia%org!i6iScanning&'nne+ing$icroscope

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http://www.chembio.uoguelph.ca/educmat/chm729/STMpage/stmtutor.htmhttp://en.wikipedia.org/wiki/Scanning_tunneling_microscopehttp://en.wikipedia.org/wiki/Scanning_tunneling_microscopehttp://en.wikipedia.org/wiki/Scanning_tunneling_microscopehttp://en.wikipedia.org/wiki/Scanning_tunneling_microscopehttp://www.chembio.uoguelph.ca/educmat/chm729/STMpage/stmtutor.htm


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scanning probe microscopy.pptx

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