나노 기술 (Nano Technology) ( gy)

(1)

NANOTECHNOLOGY

2008. 3. 13 (목) 이 길 선

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나노 기술 (Nano Technology) ( gy)

“나노미터(1nm = 1x10^-9 m : 10억분의 1미터) 크기의 물질을 조작하고 제어하는 기술”

조작하고 제어하는 기술

나노: 그리스어로 난쟁이를 의미함

사람 적혈구 DNA 원자

백두산

지구 핀 머리

m nm

(1/십억) μm

(1/백만) mm

(1/천)

km

(천) 10

³

km

(백만) (1)

(3)

나노기술의 응용

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재미있는 나노 현상

크기에 따라 색깔이 바뀌는 나노입자

(5)

재미있는 나노 현상

합성조건에 따른 다양한 모양의 나노입자

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춤추는 자성액체: 콜로이드 상태의 액체 자석

(지름 수십 f 로 안정화 $100/ )

(지름 : 수십 nm, surfactant로 안정화, >$100/g)

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나노기술역사

Si(111)-7x7

f u

Si(111)-7x7

5 nm

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나노 크기를 어떻게 관찰하는가

?

주사형 터널 현미경

(STM)

전자현미경

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여러가지 표면의 원자 배열

8x8 silicon nitride / Si(111)

f u

Si(111)-7x7 Sb/Si(111)- 3x 3

5 nm

5 3x5 3

Sb/Si(111) Sb/Si(111)-2x1 Si(100)-2x1

-

(11)

전자의 터널링 전자의 터널링

도체 절연체 도체

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분자 주판 단분자의 합성

C

₆₀

on stepped Cu surface

Fe(CO)

₂

(13)

작은 것으로부터 나노크기로 (Bottom-up 방식)

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E l Q t C l Example: Quantum Corral

D Ei l IBM

(1) STM manipulation (2) Visualization

of the spatial

D. Eigler, IBM

of the spatial distribution of certain quantum states of the

states of the corral

• Surface state electrons on Cu(111) were confined to closed

• Surface state electrons on Cu(111) were confined to closed structures (corrals) defined by barriers built from Fe datoms.

• A circular corral of radius 71.3 Angstrom was constructed in

this way out of 48 Fe adatoms.

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Atomic Manipulation by STM

Iron on Copper (111):

Circular corral

radius= 71 3 A radius= 71.3 A 48 Fe atoms

Quantum-mechanical Quantum mechanical interference patterns

M.F. Crommie, C.P. Lutz, D.M. Eigler. Science 262, 218-220 (1993).

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전자의 파동성 : STM 이미지

48 Fe atoms on Cu(111) ( )

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STM Manipulation of Atoms and Molecules STM Manipulation of Atoms and Molecules

Xenon/Ni(110) Xenon/Ni(110)

Iron/Cu(111) CO/Pt(111)

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Atomic Force Microscope (AFM) and Lateral Force Microscope (LFM)

Photodiode L

Piezo ~

Laser

Feedback and x,y,z Scan

Control

Image

Control

x,y,z Piezo Drum Scanner

Topography, LFM, etc.

×500 ×20000

< Microscope image > < FE-SEM image >

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단분자의 정렬 모양 : AFM 이미지 단분자의 정렬 모양 : AFM 이미지

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Molecular Images of Au (111) and ODT on Au/mica

Topography FFT filtered image Spacing

Au (111) 2 9 Å

Au (111) 2.9 Å

2 5 Å 2 5 Å

5.0 Å

ODT 5.0 Å

ODT

on Au/mica _{Au (111)}

4 0 Å 4 0 Å

(21)

나노기술의 기술적 접근

□ T d 방식

□ Top-down 방식

▶ 나노미터 수준의 가공을 통해 나노미터크기의 구조체를 인공적 으로 형성하는 기술 (거시적 → 미시적, 일반적인 반도체 공정)

□ Bottom-up 방식 p

물질의 최소 단위인 원자나 분자를 자유자재로 조작하여 원하는

기능 구조체를 형성하는 기술(미시적 → 거시적 예를 들면 레고처럼

기능, 구조체를 형성하는 기술(미시적 → 거시적, 예를 들면 레고처럼

각 조각을 조립하여 전체를 만드는 경우)

(22)

( )

Dip Pen Lithography (DPN)

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Dip-pen nanolithography의 개념

□ Mirkin박사는 AFM측정에서 극복해야 할 단점인 대기 중의 물분자의 기판으로의 이동을 이용하여 코팅하고자 하는 물질을 물과 함께 이동가능성을 생각

Fountain pen AFM tip을 이용한 물질전달 개념도

□ 만년필과 DPN의 비교

Fountain pen

DPN Fountain pen

AFM tip Nib (end part of pen) Solid substrate Paper

Solid substrate Paper

Molecules Ink

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Dip Pen Nanolithography (DPN)

Invention of DPN

• Capillary forces between the AFM tip and the sample → Difficult to achieve molecular resolution in air (water condensation)

Mirkin at el, Science, 283, 1999.

Advantages

Key Factors of DPN Resolution

• The grain size of substrate

Advantages

• Positive patterning

• Delivery of different types of

• Interaction between molecules and substrate

• The tip-substrate contact time and the scan speed

• Relative humidity

molecules at specific sites

• Not resist, stamp, complicated processing

Si l i i ( l AFM)

Relative humidity

• Simple instrumentation (general AFM)

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Examples of Direct Nanopatterns by DPN (Mirkin’s group)

Au (111)

Amorphous Au Au (111) Amorphous Au

Amorphous Au Amorphous Au

HMDS (hexamethyldisilazane) : (Hy ₃₃C)₃₃-Si-NH-Si-(CH₃₃)

On Oxide surfaces

Amorphous Au

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Nanofabrication: Dip Pen Nanolithography

S. Hong and C.A. Mirkin, Northwestern Univ.

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Multiple DPN - 8

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Protein Detection using DPN

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Multiple DPN - 55000

8773 dots

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Electrochemical DPN (Liu’s group)

Ag, Ge, Pd, Cu nanowires Au nanowires

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Lith h Lithography

Photolithography Photolithography E-beam lithography

Microcontact Printing (uCP) Microcontact Printing (uCP)

Imprinting

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Image Display Using Immobilized Vesicles

Immobilized diacetylene liposome

glass substrate

254 nm UV exposure

mask

+ polymerization

p

M k P tt

p y

on exposed areas

Heating at 100 ^oC

Mask Pattern

blue-to-red color transition

Observe pattern with a fluorescence microscope

Patterned Polydiacetylene Image

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Nano-meter spacing electrode fabrication p g

SiO / Si wafer

Resist coating PMMA 950K C2 SiO

₂

/ Si wafer

SiO

₂

thickness: 200 nm

PMMA 950K C2 Thickness: 80 nm

e-beam lithography

& develop PMMA

Metallization

5 nm Ti/10 nm Au Nano pattern

Channel width: 20 nm

thermal evaporation

& lift off

iQUIPS Korea Univ.

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Photo & E-beam Lithography Process

PMMA spin coating PR spin coating

E-beam Lithography Photo Lithography

PMMA spin coating (thickness: ~100 nm ) PR spin coating

(thickness: ~1 μm ) UV or laser exposure

iti ith k

e-beam exposure di t iti

development development

wafer PR mask

writing with mask direct writing

metallization lift-off

mask PMMA

exposed area metal

lift off lift off

• resist: photo sensitive polymer

• light source: UV or ArF laser

• resist: PMMA

• light source: e beam

• light source: UV or ArF laser

• critical size: ~100 nm

• light source: e-beam

• critical size: <10 nm

PMMA (polymethylmethacrylate)

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Nano Pattern Fabrication Process

(Dr. Hwang, iQUIPS, Seoul University)

( g Q y)

E-beam lithography for nano pattern fabrication

Photo lithography for pad pattern fabrication

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SEM Images of Typical Nano-Electrode

(Dr H ang iQUIPS Seo l Uni ersit ) (Dr. Hwang, iQUIPS, Seoul University)

(38)

FE-SEM and AFM Images of Nanoelectrode

7 5 0 n m 1 0 0 0 n m

(39)

E-beam patterning examples p g p

D l tt

Develop pattern Line width/spacing 1. 200 nm/300 nm 2. 100 nm/400 nm 3 50 /450

1

2

3 4 3. 50 nm/450 nm _D _l _tt

4. 100 nm/100 nm 5. 50 nm/50 nm

4 5 Develop pattern

Line width/spacing 20 nm/180 nm

Liftoff pattern

Liftoff pattern Liftoff pattern

Line width/spacing 50 nm/50 nm

Liftoff pattern 6 um diameter 150 nm line width

iQUIPS Korea Univ.

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세상에서 가장 작은 기타: 전자빔 식각 방 법

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Self-assembled monolayer (SAM) and μCP

▲ LFM images of a gold surface patterned with SAMs terminated in different head groups.

▲ SEM images of test patterns on layers of silver (A, B, C: 50 nm thick; D: 200 nm thick) that were fabricated by mCP with HDT

Angew. Chem. Int. Ed, 37, 550-575 (1998)

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Self-assembled monolayer (SAM) and μCP

Crystal growth

Whitesides et al., Nature, 398, 495 (1999)

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21세기는 나노의 시대 21세기는 나노의 시대

수학, 화학, 물리, 생물, 공학의 융합 기술

나노 기술 (Nano Technology) ( gy)

NANOTECHNOLOGY

나노 기술 (Nano Technology) ( gy)

m nm

(1/십억) μm

(1/백만) mm

(1/천)

km

(천) 10

km

(백만) (1)

재미있는 나노 현상

재미있는 나노 현상

?

(STM)

C

on stepped Cu surface

Fe(CO)

E l Q t C l Example: Quantum Corral

(1) STM manipulation (2) Visualization

of the spatial

of the spatial distribution of certain quantum states of the

states of the corral

• Surface state electrons on Cu(111) were confined to closed

• Surface state electrons on Cu(111) were confined to closed structures (corrals) defined by barriers built from Fe datoms.

• A circular corral of radius 71.3 Angstrom was constructed in

this way out of 48 Fe adatoms.

Atomic Manipulation by STM

Circular corral

Quantum-mechanical Quantum mechanical interference patterns

M.F. Crommie, C.P. Lutz, D.M. Eigler. Science 262, 218-220 (1993).

48 Fe atoms on Cu(111) ( )

Image

< Microscope image > < FE-SEM image >

Molecular Images of Au (111) and ODT on Au/mica

Topography FFT filtered image Spacing

Au (111) 2 9 Å

Au (111) 2.9 Å

5.0 Å

ODT 5.0 Å

ODT

on Au/mica Au (111)

나노기술의 기술적 접근

□ T d 방식

□ Top-down 방식

▶ 나노미터 수준의 가공을 통해 나노미터크기의 구조체를 인공적 으로 형성하는 기술 (거시적 → 미시적, 일반적인 반도체 공정)

□ Bottom-up 방식 p

물질의 최소 단위인 원자나 분자를 자유자재로 조작하여 원하는

기능 구조체를 형성하는 기술(미시적 → 거시적 예를 들면 레고처럼

기능, 구조체를 형성하는 기술(미시적 → 거시적, 예를 들면 레고처럼

각 조각을 조립하여 전체를 만드는 경우)

( )

Dip Pen Lithography (DPN)

Dip Pen Nanolithography (DPN)

 Invention of DPN

• Capillary forces between the AFM tip and the sample → Difficult to achieve molecular resolution in air (water condensation)

Mirkin at el, Science, 283, 1999.

 Advantages

 Key Factors of DPN Resolution

• The grain size of substrate

 Advantages

• Positive patterning

• Delivery of different types of

• Interaction between molecules and substrate

• The tip-substrate contact time and the scan speed

• Relative humidity

molecules at specific sites

• Not resist, stamp, complicated processing

Si l i i ( l AFM)

Relative humidity

• Simple instrumentation (general AFM)

Examples of Direct Nanopatterns by DPN (Mirkin’s group)

Au (111)

Amorphous Au Au (111) Amorphous Au

Amorphous Au Amorphous Au

On Oxide surfaces

Amorphous Au

Nanofabrication: Dip Pen Nanolithography

Nanofabrication: Dip Pen Nanolithography

Electrochemical DPN (Liu’s group)

on Au/mica _{Au (111)}

Invention of DPN

Advantages

Key Factors of DPN Resolution

Advantages

Crystal growth