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Microplasmas and Nanostructures

from Italy via Belfast to Japan

by Davide MariottiJSPS Research Fellow

at the Nanoarchicectonics Research Center(AIST)

Today Menu

• Something about Italy• Something about Me

• Plasmas• Plasmas and Nanostrctures• MicroPlasma and Nanostructures

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Something about Italy

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Italy is a Constitutional RepublicPopulation: 58 462 375

• 9 000 people over 100 years old• 4% foreigners

Surface: 80% of Japan (46% of population)21 regions2 countries within our borders(San Marino and Vatican City)1 Italian territory (Campione) within Swiss bordersOfficial language: Italian(12 other languages officially

recognized)

Some numbers

Italy & Japan

Etna

Vesuvio

Stromboli

Vulcano

Active Volcanoesand Earthquakes

Campi Flegrei

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Definitely a good team is Valentino Rossi and Yamaha!!

Italy & Japan

Sport

Comics

DIABOLIKthief for the poor people

PAPERINIKWalt Disney character created by an Italian

STURMTRUPPENsatira of the 2nd World War

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Japanese mangasSince 1978 Japanese mangas and cartoons became very popular in

Italy, especially in TV

Italian survival kit

Intesi?!(understood?!)

Te lo giuro!(I promise)

Sono pappa e ciccia(they are one thing)

Me ne infischio!(I don’t care!)

E’ tocco!(He’s crazy!)

C’ha i paraocchi!(lit. he wears blinders)(He’s narrow minded!)

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Something about …

… meI was born here

My University

Electronic Engineering

I like snowboarding here

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… then …Hyvinkaain Finland

Dublinin Ireland

Loughboroughin England

Belfastin Northern

Ireland

PhD at University of

Ulster

…Today Menu

Something about ItalySomething about Me

• Plasmas• Plasmas and Nanostrctures• MicroPlasma and Nanostructures

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Plasma?Everything You Always Wanted to Know

About Plasmas * But Were Afraid to Ask

Molecules, electrons etc.Molecules or atoms• Not positively charged• Not negatively charged• Neutral

Excited molecules/ atoms

• Neutral• Energetic• Emit light

Ions• Molecules or atoms that

have lost one or more electrons

• Positively/Negatively charged

Electrons• Have escaped from

molecules or atoms• Negatively charged

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Solid, liquid, gas … and plasmas

LIQUID• Molecule bonds are flexible• Electrons close to

molecules

SOLID• Molecules fixed in lattice• Electrons bound to

molecules or lattice

GAS• Molecules free to move• Few electrons and ions that

are free to move• Some excited molecules

are present

PLASMA• Molecules free to move

• Many electrons, ions and excited molecules, all free

to move• … and light coming out

MoleculesExcited moleculesIonsElectrons

ENERGY

ENERGY

ENER

GY

Why plasma is different from a gas?

Collisions are to blame!Gas

Plasma

Therefore more and stronger collisions leading to more

ionization,excitation,

dissociation andradiation

MoleculesExcited moleculesIonsElectrons

Ionization

Excitation

Dissociation

Differenttypes ofMolecules &RADICALS

Radiation

ENERGY

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Where can we find plasmas?

• What do they look like?

• How big are they?

• What do they eat?

Luminous like a coloured light

Inconsistent like a burning flame

Big as the universe … or small as a spark or a pixel in a screen

Consume ENERGY

QUIZwhere can we find plasmas?

• Display

• Most of the Universe

• Lights,signs

• IC Industry

• FusionEnergy And many other places

• Material processing industry• Welding, cutting etc.• Gaseous pollutants abatement• Chemical analysis• … & many more in the future,

e.g nanotechnology

• Lightning

• Flames

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How do we make a plasma?

• Provide energy! How?• Heat transfer, radiation …• … in many cases… simply by Electric Field

and we call it Plasma or Discharge

+

-

∆V

MoleculesExcited moleculesIonsElectrons

plasmagas

In nature … Lightning

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Plasma Display applications,A simple view

Front Glass

Transparent Electrodes

Spacer

Back cover of the Display

Electrodes

TOP VIEW

+

-

Plasma

Plasma Display, the real one

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Plasmas in Material processing

WHY DO WE WANT TO MODIFY SURFACES?

- To obtain different properties- To form NANOSTRUCTURES with even more different

properties

plasma

Energy & reactive speciescan change the surface

GAS

Small changes atthe surface

Sputtering and etching

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deposition

Many things can be done with plasmas … but How to control

plasmas?

• Gas content (e.g. mixture of argon, nitrogen, hydrogen, methane etc.)

• Pressure, from low-pressure to atmospheric

• Plasma system configuration

• Energy given to the plasma

• …etc.

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PSU Circuit,Transformer etc.

GasElectrons/Ions

Joule’s Effect

EM FieldWork

Ionisation

Elasticcollisions

HeatTransfer

MaterialSurface

Material

ChemicalProcesses

Dissociation

ReactiveSpeciesKinetic

bombardment

Excitation

ElectronEmission

Energy flux

Particle flux

Plasmas … not that simple

Plasmas and Nanostructures

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What does a nanostructure look like?

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Gold thin layer

Molybdenum-oxide rods on Molybdenum wire

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Carbon flakes on Molybdenum wire

Which plasma should we use for nanostructures?

A lightning would destroy everything

… what about lightning? Would a small lightning work?

… BUT … (next video)

VIDEO

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Glow-like plasmas

VIDEO

microPlasmasand

Nanostructures

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• Glow-like at atmospheric pressure

• Reduced power

• Portable equipment

• Different plasma properties all together

Why MICROplasma?

Why MICROplasma?A = Surface = 6 x r2

V = Volume = r3

AV

= 6r2

r3

6r

=

r = 10 r = 1

AV

= 6r

0.6= AV

= 6r

6=

In the smaller cube, whatever you do at the surface is 10 times more important!!!!!

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Metallic Support

Gas in

Gas out

Capillary(contains flowing gas)

Metallicwire/tubing

Substrate

Our MICROplasma

Ground/Floating

Power Supply (High/Low Freq.)

studying MICROplasmasoptical emission diagnostic

Plasma Light Emission

Spectrometer

Optical Fibre

Plasma properties

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Plasma properties

Change & improve plasma

BetterNANOSTRUCTURES

… hopefully

有難うございました

Davide Mariotti

d.mariotti at aist.go.jp

Thanks to my host

Dr. Naoto Koshizaki

and all my colleagues, in particular:

Dr. Yoshiki Shimizu

Dr. A. Chandra Bose

Thanks to JSPS

for the opportunity to come to Japan and to come here in Takasaki

Thanks to You

for your attention