1. Quantum Dots Arindam Ghosh

3. Organization of large number of nanostructures – scalability Utilize natural forces Organic, inorganic and biological systems Physics research on quantum dots What are the active areas Understand nanoscale transport Materials Self-assembly of nano-structures Paradigm shift in functional electronics? Effect of quantum mechanics Confinement and Coulomb force Spin effects and intrinsic magnetism Disorder – error optimization and modeling New nanostructured materials for transistors: Beyond silicon? Nanowires for interconnects or active elements New dielectrics: high-k and low-k Single electron transistors Carbon for next generation? New architecture? Electronics with nanomachines? Ferromagnetic logic devices? Quantum computation

4. current Gate voltage (V g ) V SD current Single electron transistors (SET) – Operation of atomic switches Particle in a small box  10 – 100 nm Energy-levels are quantized  E  1/L 2 Quantum effects only when  E>>kT current Source-drain voltage (V SD ) -V g SourceDrain V SD Source Drain Gate Quantum Dot

5. The top-down approach Plus Materials Plan/InformationTools Creates Product

6. The bottom-up approach Tools Materials with stored information Plus Creates Self-Assembled Product

7. New materials and protocols for SET 1.High-mobility two-dimensional electron gas 2.Nano-engineering with silicon 3.Semiconductor nanoparticles and nanowires 4.Carbon electronics with nanotubes and graphene 5.Molecules and DNA

8. The two-dimensional electron gas in semiconductor heterostructures Gallium Arsenide 2D electrons Aluminum Gallium Arsenide Si atoms Extremely versatile Expensive Incompatible to Silicon technology

9. Carbon nanotubes

10. The Carbon nanotube single electron transistor Source Drain Gate

11. Single electron transistor with nanotube rope

12. Structures of Quantum dot

13. Transport in single quantum dots

14. Constant interaction model

15. Coulomb blockade oscillations

16. The magic numbers The Fock-Darwin Spectrum

17. Experiment

18. Excitation spectrum

19. Quantum dot in quantum computation 1.Spin qubit in single quantum dot 2.Charge qubit in double quantum dots 3.Varying readout schemes

20. Spin measurement in a quantum dot “Spin to charge” conversion Nature 2004

21. The protocol (1) Empty, (2) inject and wait, (3) measure

22. Measuring spin

23. Experiment

24. 2D Artificial Atoms