Nano Materials and Devices (NMD)
Self-Assembly of Nanoparticles on Surfaces
The Self-assembly of Nanoparticles on Surfaces project creates and applies an integrated methodology incorporating the Density Functional Theory, Molecular Dynamics and Kinetic Monte Carlo methods to investigate the processes controlling the self-assembly and organisation of nanostructures on surfaces.
In 2009 progress in this project has proceeded along the following themes:
- Self-Ordering Behaviour of Metallic Nanoparticles on Metal Surfaces.
- Application of Kinetic Monte-Carlo to the investigation of Self-Assembly onto Surfaces.
- Visualisation and Quantification of Morphology during crystallisation and Self-ordering of Au nanoparticles.
- We are currently developing a hybrid Molecular Dynamics-Kinetic Monte Carlo code to extend the accuracy and range of self-assembly processes we can model.
- We have commenced investigating self-assembly of structures in nanopores and nanotubes.
Development and Application of Nanostructured Functional Materials
The Development and Application of Nanostructured Functional Materials project produces novel nanostructured materials with unique or enhanced properties. The nano-pigments thus produced will be used as colorants, while chromatic nanomaterials will be targeted for applications in optical devices.
Novel PNP Nanopigments
- A new class of fluorescent nanopigments, named polymeric nanopigment or PNP, has been developed. The PNP retains the fluorescent characteristics of the original dye while exhibiting enhanced colour-fastness and ultra-violet stability.
- The PNP technology has been successfully scaled up, and a licensing agreement has been signed up with a large pigment manufacturing company for commercialisation.
- A provisional patent has been lodged to protect this new technology.
- Set up an advanced nanopigment laboratory at RMIT with external support.
- Seek external funding to continue and expand the nanopigments research work and technology.
Synthesis and Characterisation of Nanostructured Devices
The Synthesis and Characterisation of Nanostructured Devices project combines advanced characterisation with plasma-based synthesis methods to develop new nanostructured devices. The project will involve interactions with other researchers in the Nano Materials and Devices program in order to develop new areas of research and enhance productivity through skill sharing.
In 2009 work has been focused on two areas:
Graphene based nanostructures for high performance devices
- Heat extraction in nanoscale systems has become a critically important issue limiting future advances in high speed microprocessors.
- We propose oriented graphene sheets, the best thermal conductor available, as a solution to this problem. The graphene sheets can also serve as electrical contacts and interconnects enabling further miniaturisation by combining thermal and electrical functions.
- We have demonstrated a method for the production of films consisting of self-assembled vertically oriented graphene sheets which form Ohmic contacts to Si. The electrical and thermal transport properties of these films are currently under investigation. Simulations of film growth and thermal transport are being performed by co-investigators at Curtin University of Technology.
High performance metal oxide thin film devices
- A filtered cathodic vacuum arc deposition system has been used to prepare high quality metal and meal-oxide films. The films have been deposited alternately to form optical filters, anodised to form nanostructured chemical sensors and incorporated into transistor structures and High-K dielectric materials.
- In separate activities, atomic layer deposition of graphene and zinc oxide has been used to produce transparent conducting coatings for photo-voltaic devices. Advanced electron-microscopy and materials characterisation techniques have been used to characterise and optimise the films and devices.
- Thermal transport and electrical properties measurements of oriented carbon layers forming junctions with various metallic layers. Investigation of hydrogen gas sensing performances of Pt/oriented-carbon junctions (with Associate Professor Kourosh Kalantar-zadeh).
- Development of on-chip thermal conductivity measurement devices and laser thermal conductivity measurements.
- Formation of prototype vertical interconnect and IC heat-sink components formed from oriented carbon.
- Characterisation of transparent conducting doped zinc oxide films (produced with Dr Andre Anders at Lawrence Berkeley National Laboratory), USA using electron-microscopy.
- Characterisation of High Power Pulsed Magnetron Sputtered (HiPIMS) carbon films (in conjunction with University of Sydney).
- Synthesis and characterisation of nano-structured metal oxide films: development of bio-coatings based on nanoporous titania in conjunction with Associate Professor Kourosh Kalantar-zadeh and Dr Vipul Bansal.
The Nanolithography project is to develop a nanolithography platform capability that will enable the realisation of a range of novel devices with nano-scale features in the areas of integrated optics, nano-electronics, sensors and biotechnology. The nanolithography platform will also provide a unique capability to support a range of discovery-type fundamental research.
- Enhancement of e-beam write capability through upgrading of RMIT’s FEG-SEM tool at the advanced microscopy unit. This enhanced capability will be operational in late 2010 and will provide 10nm write capability over areas with dimensions on the order of 100 microns.
- Obtained ARC funding to purchase wafer bonding tools which will enable encapsulation of these and other nano-features within larger scale micro-systems.
- Utilise the e-beam write tool to prototype advanced silicon photonic and polymer optical devices. These devices will fit within the write field of the e-beam tool and will make use of the ultra-high resolution patterning that can be achieved. Emphasis will be placed on the introduction of gain materials including organic dye material from RMIT’s Theology group.
- Explore the design of metal nano-textures as plasmonic elements which can be added to fibre tips or planar integrated optical devices. In particular, we will explore the engineering of surfaces for enhanced Raman sensing capabilities and explore opportunities for quantum optical behaviour in nano-scale ‘slot’ cavities and enhanced nonlinear metamaterials.
- Establish a micro-contact printing capability that will allow the use of e-beam written textures to be used as ‘rubber stamps’ which can enable complex and environmentally sensitive reagents (such as proteins) to be patterned in precisely defined and aligned arrangements. This marriage of micro/nano-lithography and biology will be key to our future work in lab-on-a-chip platforms.
Nano-engineered Multi-functional Materials for Catalysis and Sensing by an Integrated Chemical and Electrochemical Approach
The aim of this project is to explore an elegant integrated approach to nano-engineer multifunctional materials of controlled size, shape, composition and porosity through facile chemical/electrochemical methods. These nanomaterials will be designed for environmental and energy applications including the sensing and removal of mercury, electro catalysts for fuel cell related technology and nanostructured substrates for sensing of potent bio-toxins.
- The development of an Hg sensor through a project funded by industrial partners, Alcoa and BHP Billiton. This project has been highlighted on ABC radio ‘Science Show’, newspapers such as The Financial Review, websites including Sciencealert, Nanotechnology and development news, Nanotechnology Now, Nanowerk, and R&D Mag.
- This resulted in publications in Sensors and Acutators B (137, 2009, 246) and Physical Chemistry Chemical Physics (11, 2009, 2374).
- The electro deposition of gold in different active states has been probed for its electro catalytic performance and published in Langmuir (25, 2009, 2374).
- The electro catalytic and surface enhanced Raman scattering activity of Au nanospikes has been accepted in Chemical Communications (DOI:10.1039/B910830K).
- The influence of the bimetallic composition of nanosized Ag/Pt alloys has been investigated for hydrogen production and has been recently accepted in Electrochemistry Communications (DOI: 10, 1016/j.elecom.2009.06.018).
- These projects have also resulted in initiating international collaboration with IICT India.
- Explore the electrochemical and chemical synthesis of bimetallic nanostructured catalysts to alleviate catalyst poisoning effects and maximise activity.
- Develop well ordered homogeneous nanostructured surfaces with surface enhanced Raman scattering (SERS) properties that can be utilised for in-situ catalytic mechanisms determination and the detection of harmful biotoxins such as botulinum.
- Increase international collaboration and engage with CSIRO on a project to develop organic solar cells.
- Develop a mercury sensor for the detection of low levels of Hg.
Micro Platform for Lab-on-a-Chip
The objective of this project is to create polymer micro-fluidic and integrated optic platforms that can be realised using low-cost micro-fabrication ‘printing’ technology to enable fundamental scientific research in the fields of physics, chemistry and biomedicine.
- Established a lab-on-a-chip platform which is enabling research in such diverse fields as blood clotting, embryo culturing, muscle behaviour, optical physics, sensing and chemistry of nanoparticles. The low-cost, highly accessible nature of this technology has made it the basis for over 10 PhD projects.
- Enabled research at the Australian Centre for Blood Diseases to make a fundamental discovery about blood clotting - published in Nature Medicine and Lab-on-a-chip.
- Demonstrated the first use of electromagnetic trapping of nanoparticles (dielectrophoresis) to create optical elements such as waveguides.
- Establish fruitful research collaboration with biomedical researchers from RMIT’s Health Research Institute.
- Harness the advanced capabilities of the nanolithography platform program to achieve integrated opto-fluidic systems and sophisticated nano-patterned biological systems.
- Implementation of sophisticated valves, integrated sensors and computer control to enable complete lab-on-a-chip systems.