SLIDE 1 Nanosphere Lithography via Nanosphere Lithography via Continuous Convective Assembly Continuous Convective Assembly
Simranbir (Simi) Hundal Simranbir (Simi) Hundal
Chemical Engineering Chemical Engineering
Contra Costa Community College, San Pablo, CA Mentor: Erin Orazem Faculty Advisor: Dr. Steven K. Buratto
SLIDE 2
The “Big Picture” The “Big Picture”
Using Using nanosphere nanosphere lithography to produce the lithography to produce the largest possible coverage of silver triangles largest possible coverage of silver triangles Considered variables: cleaning solutions, Considered variables: cleaning solutions, nanosphere solution concentration, slide type, nanosphere solution concentration, slide type, sphere size, and withdrawal rate sphere size, and withdrawal rate
SLIDE 3 Methods Methods
Continuous Convective Assembly (CCA) Continuous Convective Assembly (CCA)
To create monolayer arrays of hexagonal closed packed To create monolayer arrays of hexagonal closed packed nanospheres nanospheres
Nanosphere Lithography (NSL) Nanosphere Lithography (NSL)
Monolayers of nanospheres used as “masks” when Monolayers of nanospheres used as “masks” when evaporating with silver to generate ordered arrays of evaporating with silver to generate ordered arrays of triangles. triangles.
2.5µm 1 µm
SLIDE 4 Continuous Convective Assembly using Continuous Convective Assembly using the Stepper Motor (Dippy) the Stepper Motor (Dippy)
Convective Assembly of the nanospheres on the slide Convective Assembly of the nanospheres on the slide Slide is withdrawn out of the solution at a particular Slide is withdrawn out of the solution at a particular rate (slow: ~60 rate (slow: ~60µ µm/min; fast: 180 m/min; fast: 180µ µm/min) m/min)
Nanosphere Solution Glass Slide Nanospheres Height 2.5µm
SLIDE 5 Nanosphere Lithography
Used to generate ordered arrays of triangles by using the monolayers of nanospheres as a “mask” for the evaporation of silver.
Ag
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SLIDE 6 Cleaning Solution: Piranha/RCA vs. Chromic/Sulfuric Acid Bath
5µm
Piranha/RCA
Piranha: Concentrated Sulfuric Acid and 30% Hydrogen Peroxide RCA: Nanopure water, Ammonium hydroxide, and 30% Hydrogen Peroxide
Chromic/Sulfuric Acid Bath
Chromium Trioxide in concentrated Sulfuric Acid
5µm
900nm spheres
SLIDE 7 Glass vs. Mica
5µm 5µm
Glass Mica
In consideration of the variables, the slide type did not have a major affect of the formation of hexagonal close packing.
900nm spheres
SLIDE 8 Withdrawal Rate
Fast rate: ~180µm/min Slow rate: ~60µm/min
5µm 5µm At the fast rate there was much more of a closed packed surface
400nm spheres
SLIDE 9
Future Plans
Optimizing evaporation conditions Optimizing variables: volume concentration, sphere size Optimizing for smaller sphere diameters, i.e. 20nm
SLIDE 10
The triangular arrays are used as substrates for surface-enhanced Raman spectroscopy (SERS). Prepare optical units, electronic Read Only Memory (ROM) devices Fabrication of periodic particle array (PPA) surfaces. Chemical and biological sensors
Applications
SLIDE 11
So What Did I Learn?
Instruments
Atomic Force Microscope (AFM): Operation and theory Stepper Motor: Operation and using Lab View program Thermal Evaporator: Operation
Research
Basics of Nanosphere Lithography and characterization using different instruments 8 weeks is not enough for research
SLIDE 12
UCSB, Department of Chemistry & Biochemistry Mentor: Erin Orazem Faculty Advisor: Dr. Steven K. Buratto Everyone in INSET Materials Microscopy Lab McFarland Group/Alan Kleiman Buratto Group: James O’Dea and Asanga Ranasinghe Israelachvili Group: Kenny Rosenburg & Intern: Kim-Lien Dinh Martin Vandenbroek: Engineering I Teaching Clean Room
Acknowledgements
SLIDE 13
Atomic Force Microscope (AFM)
Tapping Mode
SLIDE 14 Determining the height of the Triangle b
b= D*0.232
- 900nm b~ 209nm
- 400nm b~ 93nm
b= 3/2(√3-1-(1/√3))D = 0.232D
SLIDE 15 2.5µm 1 µm Nanosphere Soluti Glass Slide Nanospheres Height
5µm
5µm
2.5µm 2.5µm 2.5µm
SLIDE 16
SLIDE 17 5µm
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