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Introduction to Nanotechnology

Dr. Jing BaiAssociate Professor

Director of Graduate Studies (DGS)

Department of Electrical EngineeringUniversity of Minnesota Duluth

October 25, 20161

Outline

2

What is nanotechnology?

Applications of nanotechnology

Approaches of nanotechnology

My research on nanotechnology

3

What is Nanotechnology?

A human hair is 50,000 – 80,000 nanometers wide and grows ~10 nm every second (~600 nm every

minute)

Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications

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Why is Nanoscale So Special?• Materials at nanoscale

can have very differentchemical reactivitycompared to that in themacroscopic forms (e.g.,gold)

• Chemical reactions with nanoscale materials can be very fast due tovastly increased surface area per unit mass

• Quantum effects bring unique mechanical, electrical, photonic andmagnetic properties

• New forms of commonchemical elements atnanoscale possessspecial material properties

BuckyballQuantum wells

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Applications of Nanotechnology• Drugs and pharmaceuticals

• Nanoscale optical and electronic devices

• High-end flexible displays

• Energy devices

• Cosmetics

• Defense and security

• Nano-biotechnology

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Nanotechnology in Drug Delivery

Example: the use of nanoparticles to deliver drugs to cancer cells.Particles are engineered so that they are attracted to diseasedcells, which allows direct treatment of those cells. This techniquereduces damage to healthy cells in the body.

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Nanotechnology in Defense and Security

• Sensor system based on nanotechnology could detect biologicalagents

• Nanomaterials (such as CNT) mixed in fabrics of soldiers’uniforms could protect soldiers from dangers such as hightemperature, impacts and chemicals.

Nano-biosensor by NASA Carbon nanotube (CNT)

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Nanotechnology in Electronics

• Flexible electronic devices are stretchable and wearable. Theyhave applications in display screens, electronic interconnects,data storage and biomedical field.

• Nanomaterials (e.g., graphene, CNT and nanowires) and elasticpolymers play vital roles in flexible electronics.

Flexible electronics Graphene

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Approaches of Nanotechnology

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My Research in Nanotechnology

• Quantum-cascade lasers (QCL) – Nanoscale

lasers

• Nanostructured photovoltaic devices – Nanoscale

energy devices

• Electronic skin pressure sensor array for

colonoscopy – Nanoscale biomedical sensors

Quantum-Cascade Lasers (QCL)

One electron emits Nphotons to generatehigh output power

Typically N=20-50stages make up asingle QCL.

Electric field

ħω

ħω

Cascade effects

1111

ħω

Cross section of a QCL: Note that each layer thickness is a

few nanometers

10m

One layer

Dime coin QCL

1212

• Engineer the semiconductor band-structure to optimize the absorption range in the solar spectrum

• Incorporate the anti-reflection coating formed by nano-fibers to enhance the light trapping

Improvement of PV Efficiency Using Nanotechnology

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Solar Cells with Metallic Nanostructures

Absorption spectrum of a metamaterial absorber with array of nanospheres

Two types of fabricated nanostructures

Comparison between experimental measurement

and simulation results

Experimental verification of absorption enhancement of nano-

arrays

|E|

= 724 nm

|E|

= 600 nm m

in

max

Efficient absorber design based on plasmonic Fano resonance

14

Electronic Skin Pressure Sensor Array for Colonoscopy

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My Contact Information

Email: jingbai@d.umn.eduTelephone: (218)726-8606Office: MWAH 255URL: http://www.d.umn.edu/~jingbai/