photolithography vs. soft lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_week_lecture.pdf ·...
TRANSCRIPT
![Page 1: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/1.jpg)
Photolithography vs. Soft Lithography
1
![Page 2: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/2.jpg)
Hard Nanoimprinting Lithogrpahy
NIL Process
Sub-10nm feature size Large area (4-8 in.) High throughput Low cost
Nanonex NX-2000 Nanoimprinter Up to 4” wafer Sub-100 nm resolution Up to 300°C, 600 psi, UV
2
![Page 3: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/3.jpg)
• Low-cost, non-lithographic method to complement photolithogrpahy.
• Use a patterned elastomer such as poly(dimethylsiloxane) (PDMS) as a mask, stamp or mold.
• Embrace chemical concepts of self-assembly, templating and crystal engineering, with soft lithographic techniques of microcontact printing and micromolding.
• Shape materials over different length scales from 1 nm to 500 mm.
• Pattern two- and three-dimensional structures on planar and curved surfaces.
• Important in MEMS and biological applications.
“Soft” Lithography
Reviews: 1. Whitesides, G. M., Angew.
Chem. Int. Ed. (1998). 2. Whitesides, G. M., Chem. Rev.
(1999).
George M. Whitesides http://gmwgroup.harvard.edu/
Father of Soft Lithography
3
![Page 4: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/4.jpg)
The Core Material of Soft Lithography
Poly(dimethylsiloxane) (PDMS)
Very bendable (135° - 180°) Polycondensation Reaction:
CH3
Si O
4
![Page 5: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/5.jpg)
Unique Properties:
• High flexibility and optically transparent
• High gas permeability
• Low surface energy (21.6 ×10-3 J/m2)
• Conformal contact to almost all surfaces
• Low glass transition temperature (Tg ~ 146K)
5
Unique Properties of PDMS
Surface Modification of PDMS
O2 plasma etch Cl3SiR-X
b)
![Page 6: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/6.jpg)
6
The Science of Soft Lithography
h: 0.2-20 μm d: 0.5-200 μm l: 0.5-200 μm
CF3(CF2)6(CH2)2SiCl3 treatment
![Page 7: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/7.jpg)
7
Deformation/Distortion of Relief Structure
Pairing Sometimes, deformation is good. (More structures from a single mask.)
(Nano Lett. 4, 1657, 2004)
Sagging
Shrinking
![Page 8: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/8.jpg)
Soft Lithography Resolution
• Microcontact printing (μCP) 35 nm
• Replica molding (REM) ~2 nm
• Microtransfer molding (μTM) 1 μm
• Micromolding in capillaries (MIMIC) 1 μm
• Solvent-assisted micromolding (SAMIM) 60 nm
8
Five Components of Soft Lithography
![Page 9: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/9.jpg)
Soft Lithography Resolution
• Microcontact printing (μCP) 35 nm
• Replica molding (REM) ~2 nm
• Microtransfer molding (μTM) 1 μm
• Micromolding in capillaries (MIMIC) 1 μm
• Solvent-assisted micromolding (SAMIM) 60 nm
9
Five Components of Soft Lithography
Patterned ZnO Nanowires
![Page 10: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/10.jpg)
Principles of Microcontact Printing
• Dip PDMS stamp in ~2 mM alkanethiol ethanol solution for 1-2 minutes.
• Press PDMS stamp on gold surface for 10-20s.
Printing on Nonplanar Surface
Roll-to-Roll Printing
10
![Page 11: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/11.jpg)
Soft Lithography Resolution
• Microcontact printing (μCP) 35 nm
• Replica molding (REM) ~2 nm
• Microtransfer molding (μTM) 1 μm
• Micromolding in capillaries (MIMIC) 1 μm
• Solvent-assisted micromolding (SAMIM) 60 nm
11
Five Components of Soft Lithography
![Page 12: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/12.jpg)
12
“Soft” Replica Molding
“Rigid-Mask” Molding
Advantages of soft-mask molding: • The elasticity and low surface energy of the elastomeric
PDMS mold allows it to be released easily. • PDMS mold also enables manipulating the size and shape of
features present on the mold by mechanical deformation.
“Soft-Mask” Molding
![Page 13: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/13.jpg)
13
Manipulating PDMS Molds
Stretching Bending Mechanical Compression
![Page 14: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/14.jpg)
Soft Lithography Resolution
• Microcontact printing (μCP) 35 nm
• Replica molding (REM) ~2 nm
• Microtransfer molding (μTM) 1 μm
• Micromolding in capillaries (MIMIC) 1 μm
• Solvent-assisted micromolding (SAMIM) 60 nm
14
Five Components of Soft Lithography
![Page 15: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/15.jpg)
15
Microtransfer Molding (μTM)
• Create microstructures on nonplanar surfaces. • Make three-dimensional microstructures. • Problem: residual film.
![Page 16: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/16.jpg)
Soft Lithography Resolution
• Microcontact printing (μCP) 35 nm
• Replica molding (REM) ~2 nm
• Microtransfer molding (μTM) 1 μm
• Micromolding in capillaries (MIMIC) 1 μm
• Solvent-assisted micromolding (SAMIM) 60 nm
16
Five Components of Soft Lithography
![Page 17: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/17.jpg)
17
Micromolding in Capillaries (MIMIC)
PMMA
Colloids
Inorganic salt
ZrO2
![Page 18: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/18.jpg)
18
Principles of Micromolding in Capillaries
most always
• Small θasupport: slipping film.
• Intermediate θa
support : slipping films with shoulders.
• Large θasupport : wedge flow
Gold substrate with different prepolymers
![Page 19: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/19.jpg)
19
Rate of Capillary Filling
Square capillary:
Rate of capillary filling:
R
![Page 20: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/20.jpg)
Soft Lithography Resolution
• Microcontact printing (μCP) 35 nm
• Replica molding (REM) ~2 nm
• Microtransfer molding (μTM) 1 μm
• Micromolding in capillaries (MIMIC) 1 μm
• Solvent-assisted micromolding (SAMIM) 60 nm
20
Five Components of Soft Lithography
![Page 21: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/21.jpg)
21
Solvent-Assisted Micromolding (SAMIM)
• Choice of solvent is critical – rapidly dissolve or swell polymer, but not PDMS mold.
• Solvent – high vapor pressure and a moderately high surface tension.
• Methanol, ethanol, acetone are good; toluene and dichloromethane can not be used.
![Page 22: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/22.jpg)
22
Five Components of Soft Lithography
![Page 23: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/23.jpg)
23
Applications of Soft Lithography
![Page 24: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/24.jpg)
Photolithography vs. Soft Lithography
24
![Page 25: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/25.jpg)
• Convenient, inexpensive, accessible to chemists, biologists, and material scientists.
• Basis in self-assembly tends to minimize certain types of defects.
• Many soft lithographic processes are additive and minimize waste of materials.
• Isotropic mechanical deformation of PDMS mold or stamp provides routes to complex patterns.
• No diffraction limit; features as small as 30 nm have been fabricated.
• Nonplanar surfaces (lenses) can be used as substrates.
• Generation and replication of 3D topologies or structures are possible.
• Optical transparency of the mask allows through-mask registration and processing.
• Good control over surface chemistry, very useful for interfacial engineering.
• Applicable to manufacturing: production of indistinguishable copies at low cost.
25
Advantages of Soft Lithography
![Page 26: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/26.jpg)
• Patterns in the stamp or mold may distort due to the deformation (pairing, sagging, swelling, and shrinking) of the elastomer used.
• Difficulty in achieving accurate registration with elastomers (<1 μm).
• Compatibility with current integrate-circuit processes and materials must be demonstrated.
• Defect levels higher than photolithography.
• μCP works well with only a limited range of surfaces; MIMIC is slow; REM, μTM, and SAMIM leave a thin film of polymer over the surface.
26
Disadvantages of Soft Lithography
![Page 27: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/27.jpg)
27
Self-Assembled Monolayers (SAMs)
Oxidative addition: Hexanethiolate SAM On Au (111)
(J. Am. Chem. Soc. 114, 1222, 1992)
• The real power of SAMs stems from the ability to chemically tailor the terminal X groups of the alkanethiolate.
• Surface organic chemistry allows controlling surface wettability, adhesion, corrosion, etch protection, chemical and electrochemical reactivity, etc.
![Page 28: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/28.jpg)
28
Substrates and Ligands that Form SAMs
![Page 29: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/29.jpg)
29
SAMs with Different Head Groups
Lateral Force Microscope (Contact Mode AFM)
• μCPed HS(CH2)15CH3 followed by adsorption of HS(CH2)15COOH.
• The contrast arose from differences in the fractional force between the AFM tip and the surface in each region.
(Langmuir 11, 825, 1995)
![Page 30: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/30.jpg)
30
Patterned SAMs as Ultrathin Resists in Selective Wet Etching
4Au + 8CN- + O2 + 2H2O 4[Au(CN)2]- + 4OH-
Au+ 2CN- +[Fe(CN)6]3- [Fe(CN)6]4- + [Au(CN)2]-
Representative Au wet-etch chemistry:
![Page 31: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/31.jpg)
31
Etchants Used with Patterned SAMs
Anisotropic etching of Si (100)
![Page 32: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/32.jpg)
32
Patterning Wettability
Square drops of water held by surrounding hydrophobic lines.
Condensation Figures Microlens Arrays
Polyurethane precursors selectively wet patterned hydrophobic regions.
![Page 33: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/33.jpg)
33
SAMs Formed by μCP vs. Adsorption
Similarity between μCP and adsorption from solution. (J. Am. Chem. Soc. 119, 3017, 1997)
μCP
![Page 34: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/34.jpg)
34
μCP vs. other SAMs Patterning Techniques
![Page 35: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/35.jpg)
Invisible Materials
35
![Page 36: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/36.jpg)
36
![Page 37: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/37.jpg)
37
Doppler Effect
Doppler Effect
![Page 38: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/38.jpg)
38
Run! Run! The Flash Run!
![Page 39: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/39.jpg)
39
![Page 40: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/40.jpg)
40
Retroreflective Coatings
Retroreflection Mechanism
![Page 41: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/41.jpg)
41
The Cat and The Fish
The light is refracted toward the normal when it passes into a denser medium.
![Page 42: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/42.jpg)
42
Invisible Cloak by Zhejiang University
![Page 43: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/43.jpg)
43
Invisible Cloak by Zhejiang University
![Page 44: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/44.jpg)
44
Invisible Cloak by Zhejiang University
![Page 45: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/45.jpg)
45
n1 sinθ1=n2 sin θ2
Snell's Law of Refraction
Snell's Law of Refraction
![Page 46: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/46.jpg)
46
Invisible Cloak Effect
What heppens if “n2” is < 0 ???
Harry Potter’s invisible cloak
![Page 47: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/47.jpg)
Negative Refractive Index (n is < 0) 1. Two components:(S. Tretyakov) 1) Negative permittivity 2) Negative permeability 2. Novel metals based chiral structures (J. Pendry) 3. Applications: Invisible cloak; Invisible vehicles; Invisible coatings
Snell’s Law
47
Metamaterials
![Page 48: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/48.jpg)
48
Newton Medal Winner (2013) John Pendry, Imperial College London
Chiral Structures
Chirality: An object that can not be superimposed on its mirror image
![Page 49: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/49.jpg)
D. Smith et al., Science, 292, 77 (2001)
Copper mm-sized split rings 1. Microwave Region (>100 micrometer) 2. GHz
49
Metamaterials by Mask Etching
Permittivity
Permeability
![Page 50: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/50.jpg)
W. Padilla et al., Science, 313, 1495 (2006); Optics Express, 16, 7181 (2008)
1. Negative reflective index at near- IR region. 2. THz 3. Small features results in higher frequency & narrowband wavelength.
36 μm
GaAs Wafer
Polyimide
Au/Ti Wire
50
Micrometer Scale Metamaterials
![Page 51: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/51.jpg)
J. Pendry et al., Science (2004)
E. Plum et al., J. Opt. (2008)
N. Zheludev et al., Appl. Phys. Lett. (2009)
51
Spiral Metamaterials
N. Zheludev et al., Phys. Rev. (2007)
![Page 52: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/52.jpg)
Ag Wires
Al2O3
(60 nm wire dia., 110 nm spacing)
1. Negative R. I. at IR Region 2. Limitations 1) 2 D 2) Strong energy losses 3) Fabrication difficult 4) Limit band of frequency 5) Angle dependent transverse electric
transverse magnetic
500 nm
4.5 μm
52
Metamaterials by Anodization
X. Zhang et al., Science, 321, 930 (2008); Nature Materials, 8, 568 (2009)
![Page 53: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/53.jpg)
21 Layers
X. Zhang et al., Nature, 07247, 1 (2008) 53
Metamaterials by FIB Milling 1
1. 3D structures, 2. R. I. shifts in microwave region (Fabry–Pe´rot effect).
![Page 54: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/54.jpg)
Imitate reflection of flat surface on dielectric substrate
1. Hole (110 nm) arrays 2. Low energy loss 3. Broadband wavelength ( 1400 nm ~ 1800 nm)
54
Metamaterials by FIB Milling 2
X. Zhang et al., Nature Materials, 8, 568 (2009)
![Page 55: Photolithography vs. Soft Lithographyweb.nchu.edu.tw/~hyang/courses/che6842/4th_Week_Lecture.pdf · (J. Am. Chem. Soc. 114, 1222, 1992) • The real power of SAMs stems from the ability](https://reader035.vdocument.in/reader035/viewer/2022070702/5e66b5722133fa6e6f515a1a/html5/thumbnails/55.jpg)
X. Zhang et al., Phys. Rev. Lett., 102, 023901 (2009)
20 μm
Permittivity Permeability
Refractive index
Fresnel’s Reflection
55
Circularly Polarized Wave Metamaterials