My prime research interests are centred around understanding and controlling the physics of nano and atomic scale processes that occur at surfaces. This includes fundamental research into the behaviour of atoms and molecules at surfaces and the development and deployment of new nanolithographic techniques, strongly impacting on the fabrication of nanoscale electronic devices and atomic-scale components for quantum computers.
Describing my research into atomic manipulation with STM to Dr Brendan Nelson, Australian Minister for Defence.
The controlled incorporation of phosphorus in silicon with atomic-scale precision: STM images show rows of hydrogen terminated silicon dimers. The left cross-hairs show an area where hydrogen has been deliberately removed by the STM tip. After exposing the surface to phosphine gas and heating to 350ºC, a single phosphorus atom is incorporated in the surface, see right cross-hairs.
These two sequences of STM images show how subtle differences in reaction pathways can drastically effect surface processes. When PH3 adsorbs on a surface it spontaneously dissociates to PH2+H. Whether the P atom becomes trapped at one place on the surface or is free to wander around depends on whether the PH2 fragment diffuses before falling apart.
A device fabricated using atomic force microscope (AFM) lithography. Just (25nm) below the surface of this GaAs wafer is a 2-D sheet of electrons. A narrow 1-D channel is defined in this sheet by local depletion using the AFM. Depletion is achieved by forming an oxide below the tip of the AFM (a process known as local anodic oxidation) and tracing out the lines seen in the image. Electrons travel ballistically through the channel due to their long free mean path in GaAs and form widely spaced sub-bands due to their confinement within the 1-D channel, resulting in unexpectedly high operating temperatures.
This academic year I am teaching the undergraduate course ELEC1011: Circuit Analysis & Synthesis I. I have previously taught the undergraduate course Solid State Physics (PHYS3080) and postgraduate course Advanced Semiconductor Devices (ELEC9501) at University of New South Wales, Australia. I have also developed new undergraduate laboratory experiments i.e. Studying the kinetics of graphite oxidation using a STM - An undergraduate laboratory experiment, N.J. Curson, et al., European Journal of Physics, 20 453 (1999).