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Nanodevices and nanostructures:
quantum wires and quantum dots
ECE 423 Final Project
Wan-Ching Hung
Dec 12,2006
Quantum Dots and Quantum
Lines



A quantum dot typically contains between 1
to 200 atoms in diameter and its length,
width, and high are generally defined less
than 100nm.
The electron is retrained by Fermi wavelength.
Quantum dot is confined in 3 dimensions and
quantum line is confined in 2 dimensions.
Quantum Dots Applications


Si single electron
transistors
Quantum Computer
Quantum Dots Applications

Nanobarcodes

nanobarcodes are made
different quantum wires of
different metals that have
different reflectivity.

Molecule capsule in
drug delivery system
Quantum Confinement

Under 100nm, the
wave property of
electron can not be
ignored.
L
n

2
n2h2
En 
8mL2
d 2 2m
 2 ( E  V )  0
2
dy

Tunneling Effect
Coulomb Blockade

a Coulomb blockade
is the increased
resistance at small
bias voltage of an
electronic device
comprising at lease
one low-capacitance
tunnel junction.
Bottom-Up
Self Assembly

Applicatoins: solar cell, light-emitting
diodes, capsule in drug delivery system
Chemical Colloidal Method
Lithography and Etching


Lithography: electron beam, ion beam,
nanoimprint, dip pen nanolithography
Etching: wet etching, dry etching,
plasma, implantation, photo etching
Split-gate Approach


Use additional voltage to create 2
dimensional confinements to control the
shape and size of the quantum dot’s
gate.
It’s a combination of e beam
lithography, evaporation, lift off, contact
annealing