My main research interest is in the properties of nanometre scale particles (called 'atomic clusters') and in developing ways of building nano-electronic devices from these clusters. My group are currently working on cluster-based devices with applications ranging from chemical sensors to magnetic field sensors to transistors. We also have a unique apparatus for studying unusual atomic arrangements within these particles, including 5-fold symmetric structures forbidden in ordinary crystals.
This work forms part of the programme of the The Nanostructure
Engineering Science and Technology (NEST) Group at the University of Canterbury,
which is engaged in research into the fabrication and properties of a variety
of nanometre scale structures. The group has a range of interlinked
projects and a wide range of fabrication and characterisation equipment
(see also more equipment information here).
The group has strong links with researchers in the other main centres of
New Zealand as a key Partner in the
MacDiarmid Institute for Advanced Materials and Nanotechnology.
March 2003. Nanoflower structures produced in the cluster group for the first time.
March 2003. Templated cluster assembled nanowires produced with 100nm widths.
December 2002. Templated cluster assembled nanodevices first produced.
30 November 2002. Conference paper presented at ISSPIC-11 accepted for publication in European Physical Journal D. Download in PDF form
17 May 2002. The cluster group's first paper on cluster assembled nanodevices is published in Physical Review Letters. Download in PDF form.
7 May 2002. NZPIXELS programme receives 3 year funding from the New Economy Research Fund (NERF). This is part of the Compact Muon Solenoid (CMS) collaboration at CERN to develop new silicon based pixel detectors. The detectors will be used in the new generator CMS particle detector for the Large Hadron Collider, and will be tested using the cluster group's electron diffraction apparatus.
2 May 2002. New article published in the business press. 'A really, really big business opportunity', by Simon Brown, NZ business magazine, May 2002, made available in PDF form here by permisson of www.profile.co.nz.
6 March 2002. Minister of Education, Steve Maharey, announces the formation of five Centres of Research Excellence in New Zealand. The NEST group was successful in its bid to form the MacDiarmid Institute for Advanced Materials and Nanotechnology, with partners the School of Chemical and Physical Sciences at Victoria University of Wellington and Industrial Research Limited. This additional funding will provide the NEST group with a significant injection of new equipment and new funding for postdoctoral fellowships and studentships.
[How the COREs were selected: click here].
12 November 2001. Dame Silvia Cartwright, the Governor General of New Zealand visited the NEST Group. This photograph shows Simon Brown attempting to explain the importance of nanotechnology, watched by Maan Alkaisi and Steve Durbin (also members of NEST, from the Department of Electrical and Electronic Engineering).
August 2001. First NZ patent filed for a nano-electronic device.
4 July 2001. The following article
is a summary of ongoing research across the extended group, including NEST
group members in Christchurch and other researchers around the country. It
is a precis of an Invited Overview lecture to be presented by Simon Brown
at the 10th National Physics Conference PHYSIKOS2001 and 'A Celebration of
New Zealand Physics' (NZIP2001), Wellington, New Zealand. 4-6 July 2001.
Download in PDF format
The research in this group is now focussed on two main objectives. The first is to understand fundamental issues in the formation and growth of unusual atomic structures that are observed for atomic clusters (i.e. nanoscale particles formed in the gas phase leading to molecular beams). The second is to use atomic clusters as building blocks for the formation of nano-electronic devices. Both of these projects have been very succesful in the last few years and are essentially unique i.e. we are not aware of other groups who are attempting such studies.
Other research topics are based around spectroscopic studies of varies semiconductor structures, either grown or etched to form nanoscale structures. Particular emphasis is given to work on Gallium Nitride, which has important technological applications as it is the only known material suitable for blue light emitting opto-electronic devices.
Main research projects
Deposition of Atomic Clusters
A schematic of a chain of clusters formed by low energy deposition onto a lithographically modified substrate. By taking advantage of an understanding of certain aspects of percolation theory, and using a carefully designed set of contacts, we are able to ensure that the clusters form a nano-wire like structure.
2) The structure of atomic clusters.
An icosahedral Pb cluster. Note the five-fold symmetry. The structure was calculated using molecular dynamics and atoms with different symmetry positions are labelled with different colours using common neighbour analysis.
3) Deposition of antimony and bismuth onto HOPG
4) Molecular dynamics simulations of cluster structure
5) Optical studies of Reactive Ion Etched GaN
6) Optical studies of amorphous GaN and GaN / AlN superlattices.
Additional Research Interests