Findings at the University of Huddersfield (UoH) will provide positive encouragement for manufacturers worldwide whom are under pressure to develop increasingly minute computer chips, transistors and other products. The unique features of the process are that it could be used to transform the properties of nanoscale materials which can cause greater damage than previously realised.
The University houses the Electron Microscopy and Materials Analysis Research Group (EMMA) headed by Professor Stephen Donnelly, and an advance facility named the Microscope and Ion Accelerators for Materials Investigation (MIAMI). The facility is employed to bombard materials with ion beams and to examine the effects at the nanoscale.
The experimental reported, included working with a Research Fellow, Dr Graeme Greaves, was in employing a number of Gold (Au) nanorods which were irradiated with Xenon (Xe) atoms. The elements of the experiment were a good subject, because the nanowires or rods had a larger surface area. As stated by Dr Greaves - "we were hoping to generate bubbles. We actually found that we were eroding the nanowires,"
The research findings uniquely measured the rate of erosion dubbed by the researchers as the "sputtering yield" or how many atoms came out of matter for each incoming atom. Such a metric was well in advance in what the researchers were expecting.
Dr Greaves continues to state -"The sputtering yield of a normal piece of flat Gold should be of the order of 50 atoms per ion" - and - "In the case of rods we expected it to be greater, because the geometry is much reduced. We worked out that it should be higher by the factor of four, or something of that order. But we actually found that the greatest value measured was a sputtering yield of a thousand - a factor of 20."
The University was so surprised by the results that Professor Kai Nordlund of the University of Helsinki (UoH*) was asked to run a molecular dynamics simulation, which created a virtual Au nanorod. It was found that the Finnish researchers were able to replicate the findings of their co-researchers in the UK. Subsequently the findings were published in Physical Letters Review.
Dr Greaves concluded in stating that - "The research has considerable implications, particular for medicine" - and - "More and more people are working on nanostructures for practical applications. Gold nanoparticles can be used for tumour detection, the optimisation of the bio-distribution of drugs to diseased organs and a radiotherapy dose enhancer. Components of computer chips are very small nowadays - in the order of 20 nanometres in size and getting smaller - and ion beams are used to change the properties of these materials. Our research shows you must be very wary of the amount of damage that may be done." Original article available here