235 Views

Download Presentation
##### Quantum Dots

**An Image/Link below is provided (as is) to download presentation**

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -

**Quantum Dots**ArindamGhosh**Physics research on quantum dotsWhat are the active areas**• Understand nanoscale transport • Materials • Self-assembly of nano-structures • Paradigm shift in functional electronics? Organization of large number of nanostructures – scalability Utilize natural forces Organic, inorganic and biological systems 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**Single electron transistors (SET) – Operation of atomic**switches Quantum Dot Gate Particle in a small box ~ 10 – 100 nm Energy-levels are quantized DE ~ 1/L2 Quantum effects only when DE>>kT Source Drain VSD VSD Source Drain current -Vg current current VSD Source-drain voltage (VSD) Gate voltage (Vg)**The top-down approach**Materials Plus Plus Creates Plan/Information Tools Product**The bottom-up approach**Self-AssembledProduct Creates Plus Tools Materials with stored information**New materials and protocols for SET**High-mobility two-dimensional electron gas Nano-engineering with silicon Semiconductor nanoparticles and nanowires Carbon electronics with nanotubes and graphene Molecules and DNA**Si atoms**Aluminum Gallium Arsenide Gallium Arsenide The two-dimensional electron gas in semiconductor heterostructures 2D electrons Extremely versatile Expensive Incompatible to Silicon technology**The Carbon nanotube single electron transistor**Source Drain Gate**The magic numbers**The Fock-Darwin Spectrum**Quantum dot in quantum computation**Spin qubit in single quantum dot Charge qubit in double quantum dots Varying readout schemes**Spin measurement in a quantum dot**“Spin to charge” conversion Nature 2004**The protocol**(1) Empty, (2) inject and wait, (3) measure