رابطة المبعوثين العائدين من الخارج برعاية ا.د./ فرحة الشناوي

1. رابطةالمبعوثين العائدين من الخارجبرعاية ا.د./ فرحة الشناوي الندوة المجمعة الأولى تكنولوجيا النانو 1 2 د/عبد الكريم أبو الوفا ا.د./محمد نبيل صبري كلية العلوم كلية الهندسة Nano wires Nano devices

2. What is nanotechnology? 1n 0.1n 10n 100n 1m 10m 100m 1cm 1m H2O DNA Virus White blood cell Human hair NEMS/MEMS • Nano devices • Nano tubes • Nano transistors • Quantum dots • ... No sharp Frontiers! 100m

3. Why is it special? • Ability to act on phenomena • previously uncontrolled: • Physical properties • Chemical reactions • Biological transformations This lecture is mainly about: Potentials AND Risks

4. How is it fabricated? Two approaches Top – down Bottom – up (self ) Assembling tiny objects into Nano devices Cutting a nano piece out of a bulk (used in microelectronics) H-bond DNA-like molecules Assembles to:

5. Top – Down main processes • Lithography • Photolithography • Electron beam lith. • Ion implantation • Thermal treatment • Etching • Wet etching • Dry etching • Deposition • Chemical Vapor Dep. CVD • Physical Vapor Dep. PVD • …

6. Top – Down example: a nano-switch 1 Patterning 2-Photolithography 1-LPCVD Si3N4-125n Photo-resist Si-125m 3-Reactive Ion Etching RIE (He + SF6) Exposing 4- Wet Etching (KOH)

7. Top – Down example: a nano-switch 2 6-Resist + Deposition of Cr (60n) + Electron beam lithography 5-Patterning 1m 7- Deposition of Cr (5n) + Au (70n) 8-RIE

8. Carbon Nano Tubes (CNT) Take a sheet of carbon atoms … Roll it! Carbon Nano Tube: Strength = 100 x Steel; Weight = 1/6 x Steel You still need to assemble many of them to be useful! Prof. Richard Smalley (Rice U.): “it would take a single nanoscopic machine millions of years to assemble a meaningful amount of material.!” Eric Drexler believes assemblers could replicate themselves, resulting in exponential growth. http://science.howstuffworks.com/nanotechnology4.htm

9. Bottom – Up example: a cantilever Cantilever beam material Creating cantilever structure Fe2O3 nano particles Polyelectrolyte CNT

10. Biomedical Applications Lab on a chip Manipulating drops (micro-fluidic) (video)

11. Detecting Molecules “Artificial nose”!

12. Drug delivery systems

13. Nano devices are smaller than cells Nano devices can easily enter in cells for early detection of cancer In vivo Cell size: 1 – 2 m National Cancer Institute

14. More efficient cancer test National Cancer Institute Each cantilever can capture one specific type of molecules Cantilever bending: electronically detected

15. Nano-pores help reading DNA code Nano-pores: DNA passes through one strand at a time, DNA sequencing more efficient. Monitor shape & electrical properties of each base, or letter, Hence, decipher the encoded information, including errors associated with cancer. National Cancer Institute

16. Nano-pores in Aluminum 100 n

17. Using CNT to detect DNA defects A Nano-tube (sharp edged pin) Traces the shape of DNA, making a map National Cancer Institute

18. Using quantum dots to detect cancer Quantum dots: Crystals (few nm) with size dependent optical properties UV stimulus: They glow (size dependent color) Can be designed to bind to specific DNA sequences. (to detect and treat cancer cells) National Cancer Institute

19. Dendrimers: the complete solution! Cancer Cell Cancer detector Drug Cancer detector Cell death Monitor Dendrimers Man-made molecules (~ a protein). Shape gives vast amounts of surface area Can attach therapeutic agents or other biologically active molecules.

20. Programmable nano – robots! A near future dream! Patients will drink fluids containing nano-robots programmed to attack and reconstruct the molecular structure of cancer cells. Nanorobots could also perform delicate surgeries more precise than the sharpest scalpel [source: International Journal of Surgery]

21. Nano for Energy 4th Generation Solar Cells Fuel Cells Energy Harvesting

22. Solar Energy World electric power demand: ~ 14 TW Incident Solar power: 120, 000 TW!! Consider 10% efficiency, & exclude oceans and cities: 600 TW Average extractable power from Egyptian desert alone: 15 TW

23. $ 0.1/ W $ 0.2/ W $ 0.5/ W 100 Thermo- dynamic Limit 80 Efficiency (%) 60 $ 1.0/ W III 40 Theoretical Limit 20 $ 3.5/ W I IV 0 100 200 300 400 500 II Cost $ / m 2 Solar energy economics Not only efficiency matters, but also cost! Prof. Rastogi, Binghamton U. Expected grid parity: year 2012 – 2018 (depending on region) [source iSupply Applied Market Intelligence]

24. Nano pillars for solar cells Radiation losses due to reflection Anti Reflection Coating Using Nano Pillars 900n

25. Thin film solar cells Prof. Rastogi, Binghamton U. Thin film:  small amount of Si (+amorphous Si)  Low initial price Flexible:  low installation cost

26. Quantum dots for solar cells – 1 Conduction band Energy Band gap Incident Photons Donors level Electrons Losses for both too high and too low energy photons Need to have “adjustable” band gaps ?? Valence band

27. Quantum dots for solar cells – 2 Conduction band Energy Band gap For Quantum dots: Band Gap is size dependent: Make many sizes to capture all incident photons Small size: Highly excited electron can share energy with another one Valence band

28. Fuel cells Fuel can be H2 or other hydrocarbons Heat (~85oC) Membrane (heart of the device) passes H ions only Platinum catalysts Can power Handheld devices Up to trucks

29. Environmental impact of burning fuel U.S.

30. Nano improvements of fuel cells • Higher efficiency membrane • Higher surface area and lower quantity of catalyst (Platinum) • New less expensive catalyst materials

31. Energy harvesting: Thermo-ionic effects DV (open circuit) = S (Thot – Tcold) S: Seebeck Coefficient • Materials A & B can be: • Two different metals • Semiconductors with different doping When connected to a load: DV W = h Qhot h < 1 – Tcold/Thot Material B Material B Power W(W) h increases with: S, s (elec cond) h decreases with k (thermal cond) Material A Thot Tcold Figure of merit Z = S2s/k Metal/Semiconductor Nano composites: Very High Z Heat Qcold (W) Heat Qhot (W)

32. Nanopiezotronics

33. Energy harvesting: nano brush Zinc oxide nano wires 4-layer integrated nano generator: Output power: 0.11 µW/cm2 at a voltage of 62 mV.

34. Nano Electronics is here since long! A transistor Oxide thickness ~ 10n Gate Source Drain Channel length < 45 nano

35. Major problem: heat! The growing power density (measured in W/cm2) of Intel's microchip processor families. (Source: Intel)

36. R&D issues in thermal effects • Modeling & Simulation • Multiple Physics (Mainly Electro-thermal) • Multiple Scales (transistor  data center ) • Compact Thermal Models: • New technology for multiple source problems: 3D – ICs, SoC… • High performance simulation/optimization tools • Micro-fluidics & micro heat transfer • Micro-channels • Micro effects in 2 phase: Electro wetting/micro-boiling • Integrated micro/nano coolers • TACS Temperature Aware Computer Systems • Thermal aware layout • Thermal aware operating systems (ex: scheduling …)

37. Other R&D trends • Flexible flat display panels using nanowires • NEMS for high density memory (terabyte/ in2) • Molecular sized transistors • Self aligned nanostructures to build integrated circuits

38. Nanotechnology impact on environment Pros: • A high potential for new and renewable energies • Less CO2 emission • A high potential for pollution detection • A high potential for water treatment: • Composition detection • Desalination • Waste water treatment • Solution of many health problems

39. BUT …! Nanoparticles may accumulate in vital organs, creating a toxicity problem. • Use of toxic, basic or acidic chemicals organic solvents • 99% of materials used are not in final product • Actual manufacturing of nanodevices is highly energy intensive • Unknown impact of nanoparticles on natural cells

40. Conclusion • Nanotechnology is not the future, it is the present and the near future • Nanotechnology has highly promising applications in almost all engineering, medical, environmental … issues. It is inherently multi-disciplinary • Side effects, potentially harmful, are not yet quite well assessed.

41. app_micro_drop_merge.avi • app_micro_Tjunction3D.avi