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2-D Nanostructure Synthesis (Making THIN FILMS!)

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Presentation on theme: "2-D Nanostructure Synthesis (Making THIN FILMS!)"— Presentation transcript:

1 2-D Nanostructure Synthesis (Making THIN FILMS!) http://www.youtube.com/watch?feature=player_embedded&v=LFoC-uxRqCg#http://www.youtube.com/watch?feature=player_embedded&v=LFoC-uxRqCg#!

2 Examples of thin films: Hydrophobic coating on windshield Plating on a car bumper Anti-reflective coating Solar cells have a transparent conductive coating Soap bubbles Gasoline puddle

3 1-10 -3 Rough Vacuum Science 101 Pressure: The result of gas particles colliding & exerting force Vacuum: The absence of pressure (or very little pressure) Atmospheric Pressure ~ 760 torr For film deposition, decrease pressure < 10 -3 torr – Particles don’t collide into each other very often – Particles mostly collide with surfaces Decreasing pressure Medium High Ultrahigh (UHV) 10 -3 – 10 -6 10 -6 – 10 -9 < 10 -9 Instruments: Surface / Analytical Sputtering; CVD Electron microscopes P (torr) 

4 Some Terms… Source: The same chemical as the species, just in a different state of matter, size or location (Ex: Gold) Species: The chemical you wish to grow (ex: Titanium Oxide) Substrate: The surface you are growing the thin film on (ex: Silicon)

5 Physical Vapor Deposition (PVD) Involves the transferring of the species from source to a substrate (ex: Vaporized gold is transferred to a substrate and deposited as a thin layer of gold atoms) Thickness: 0.1 nm - millimeters 2 main types: #1: Evaporation (heat) #2: Sputtering (impact of plasma)

6 Evaporation Source material is evaporated Material deposits on substrate Vacuum (10 -3 – 10 -10 torr) Control concentration of growth species in vapor Fun fact, it’s $60,000 for one of these! Intel, for example, has many of these instruments

7 Demo: Beaker & watch glass

8 Sputtering Argon plasma (Ar + ) accelerated towards target As Ar + hits target, neutral atoms are ejected Ejected atoms deposit on substrate

9 Challenge: Make a model!

10 Chemical Vapor Deposition Similar to PVD, but reactions between two gases to produce a solid deposit on a substrate

11 Self-Assembly Ordered arrangement of molecules that occurs spontaneously due to forces (e.g. chemical reactions, electrostatic attraction) Chemical bonding between molecules and substrate, as well as between molecules – Sulfur LOVES Cu, Ag, Au

12 2D Film Synthesis: Coating Methods Dip-Coating: – Immerse, Deposit/Drain, – Evaporate, Repeat Spin-Coating: –Deliver sol to substrate center –Spin up; Spin-off –Evaporate; Repeat Resulting Films are porous & amorphous —Unique properties (low thermal conductivity) —Applications (electrodes in solar cells)


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