structure vs. property relationship of individual/ few nanostructures ("artificial atoms") and of assemblies of nanostructures ("artificial materials");
	developing new methods to investigate these relationships
	applications (CLICK HERE TO GO TO THE NATIONAL NANOTECHNOLOGY INITIATIVE WEBSITE)

NEW SCIENCE:

    An electron's motion, spin and charge are all quantum in nature.  At very small scales, this quantum nature of electrons gives rise to important phenomena such as discrete energy levels, bonding, Pauli's principle, magnetism, etc.  These phenomena have been well studied at the atomic and molecular scales; however, they have not been as well studied at nanometer scales primarily because of the limited choice of suitable nanoscale systems available for study - that is, until recently. 

    Over the past decades, there has been a tremendous acceleration in the development of new nano-architectures with unprecedented control over chemical composition, size, shape and geometry.  These architectures include various types of metallic, semiconducting and superconducting structures in the form of nanoparticles, rods, tubes, shells, films, etc. The variety of organic molecules that can be synthesized is, ofcourse, huge.  This progress affords new opportunities to study the above mentioned phenomena in a new regime and leads to new science.  Exploiting this opportunity, our group has confirmed some effects that had been predicted by theory but had not been observed (e.g. oscillation of resistance of granular films arising from "reflectionless tunneling") , and we have discovered still others (e.g. electron hopping in granular films over longer and longer length scales as electrons become delocalized - an effect we call "quasi-localized hopping").  Given the variety of structures that are now available and myriad ways in which they can be combined, nanoscience continues to be a target of opportunity.

New technology:

    Given control over a nanostruture's size, shape and chemical composition of matter, one can control the nanostructure's properties.  This has led and continues to lead to new applications.  Here are a few examples: 

● Samsung carbon nanotube-based colour active matrix electrophoretic display - 14.3" colour e-paper;

● Cyrium Technologies uses semiconducting nanoparticles to increase the efficiency of solar cells for concentrator photovoltaic applications;

● Nanostructured electrodes enable Li-Ion batteries with improved performance; e.g. see A123 Systems, NEI Corporation and the following references

● Re rapid charging/discharging for high power applications, see...

"Battery materials for ultrafast charging and discharging", B. Kang & Gerbrand Ceder, Nature, 458, 190, 2009 from which the above graphic was obtained

● Re improved performance, see...

"Nanostructured electrodes for Next generation rechargeable electrochemical devices", Singhal et al., J. Power Sources, 129, 38, 2004

● Increased surface area in nanofilms enables so called "supercapacitors" or "ultracapacitors" used to store/release large amounts of energy rapidly in vehicles; e.g. see Honda's FCX Ultra-capacitor...

 

Education:

Students working in this field receive a tremendously broad education.  They learn about:

    - materials by making their samples, be it via fabricating nanostructures from atomic species or assembling purchased

      nanostructures (using self-assembly or sintering);

    - building equipment, e.g. machining parts or assembling commercial components;

    - building simple electrical circuits;

    - writing data acquisition and analysis software;

    - interpreting data using the literature;

    - writing papers (all PhD students from this group have published 3-6 papers); and

    - giving talks at grad seminars and conferences.

 All PhDs from this secured employment applying this training!    

 

Fun

Also an important consideration!  Click here to read an excerpt of Feyneman's famous 1959 lecture on nanostructures

 

Techniques we use:

charge transport:

	measure charge transport properties while varying temperature and voltage
	magnetoconductance measurements
	tunneling measurements (break junctions and planar tunnel junctions)
	scanning tunneling microscopy and hybrid scanning tunneling -atomic force microscopy
	electrochemistry

optics:

	ultraviolet visible absorption spectroscopy
	Fourier transform infra-red spectroscopy

Sample preparation:

	various types of nanoparticles (size, composition varied)
	various types of molecule-linked nanoparticles (molecular linker, films architecture varied)
	thermally depositing and sintering films

More details and results:

click in the table below for more information about a particular entry

Click here for publications