Scientists at the University of Bristol now have a new tool that will yield yet more and unprecedented levels of information without disturbing the physical state of the object under scrutiny.
Physicists at Bristol’s Interface Analysis Centre have been using the Helios dualbeam instrument, which “unlocks the key to a whole new world,” says Centre Director Dr Tom Scott. The dualbeam looks at surface structures with a resolution of less than a nanometre – the equivalent of ten millionths of the thickness of a human hair. The resolution of the images produced is just one nanometre, one millionth of a millimetre.
The dualbeam uses a focused ion beam (FIB) and a high spec field emission scanning electron microscope (SEM) with gallium ions derived from a liquid metal ion source that are directed at the surface in a tightly controlled beam . The ion beam can be precisely controlled to remove material from tightly defined areas – essentially performing micro and even nano-surgery on almost any material.
Unlike other techniques used for dissecting materials, the dualbeam can extract information and capture images without causing any detectable damage except over a tiny area. It can also deposit materials such as gold and platinum, known for their conductivity, on to the surface structure, providing insights into the composition and behaviour of materials.
For physicists looking for quantum wells, biologists looking at the structure of membranes in the ears of tree crickets, and engineers keen to understand the nanostructure of exotic alloys, the dualbeam is invaluable.
“It makes things possible which were previously considered impossible, it’s at the heart of what makes science beautiful,” says Dr Scott. “It can do things in such a precisely defined way to such a high degree of accuracy that it really is incredible. In fact, it’s difficult to comprehend just how small a scale this thing works on.”
Some of the project proposals under consideration that would make use of the dualbeam include an examination of the ears of Indian tree crickets, where the dualbeam could be used to slice and view in three dimensions reconstructions of cricket ears. The findings could ultimately inform medical advancements in hearing devices for humans.
The dualbeam could also be used in quantum cryptography, to devise ways of transmitting messages in a way that is resistant to attempts to tap into the source, using emitters constructed from a single photonic light source so small and so intricately encoded as to be virtually undetectable.
In biochemistry, researchers are looking at making actuators – “gold sandwiches” with a polymer filling which could swim through the bloodstream, collecting information that could be used to inform medical approaches to human disease.
Dr Scott is keen to seek out other collaborations that will test the boundaries of every discipline: “The dualbeam instrument is a clear example of the University’s commitment to groundbreaking developments in research,” he said. “If we are going to be the leaders in the UK and internationally in terms of research we need to be pushing the boundaries of what is technically possible, and this new piece of equipment will certainly enable us to do that.”
- FEI Wins Multi-System Order from CANMET Materials Technology Laboratory (nanotech-now.com)
- Maskless GaAs etching reaches 10 nm resolution (nanotechweb.org)