Dr. Sarah Haigh is a Reader in Materials Characterisation at the University of Manchester. Her research interests centre on improving our understanding of nanomaterials properties using transmission electron microscope (TEM) imaging and analysis techniques. Sarah completed undergraduate and doctorate degrees in material science at the University of Oxford, and before moving to her current position at the University of Manchester in 2010 she worked as consultant application specialist to JEOL UK.
“…Often atoms are a bit camera-shy and run away from the electron beam so you have to be quick or they disappear. Other times they are more relaxed and let you take videos of them dancing…”
Discovering material science
I hadn’t heard of material science until I got to choosing courses for university. I saw an open day in material science advertised at the University of Oxford and when I asked my chemistry teacher what it was he said: “No idea – go and find out.” When I learned more about the subject it seemed to cover the best bits of subjects I enjoyed (physics but with less boring space stuff, chemistry with fewer reactions to learn, engineering but with less drawing circuit diagrams). It also seemed to have an element of scientific “detecting” which really appealed – probing deep inside a material to find out what makes it behave as it does.
Becoming a researcher to find things that no-one else has seen before
For me, being an academic means juggling so many balls in the air there is not a typical day – this is one of the things that makes it fun, but also exhausting. Meetings with research students (trying to understand or effectively present new results) are some of the best bits and I make time to do experiments myself a couple of times a month.
The reason I became a researcher is because I really enjoy finding things that no-one else has seen before. To do this in my research I use very high-power microscopes that use electrons to see inside a material and look at the arrangement of the atoms. Often atoms are a bit camera-shy and run away from the electron beam so you have to be quick or they disappear. Other times they are more relaxed and let you take videos of them dancing.
Graphene – the wonder material
Graphene was a material that the scientific community thought could not exist – the energy of a material just one atom thick was predicted to be too large to allow it. However, in around 2004, Andre Geim and Kostya Novoselov decided to investigate it anyway because it was also thought to have lots of interesting electronic properties.
Once they did successfully isolate graphene and begin investigating its properties they found it had huge potential – not only for its electrical properties. It was also incredibly strong and stiff, almost transparent, a great conductor of heat as well as electricity. This wide range of ‘best in class’ properties have understandably attracted great interest from scientists, industry and entrepreneurs all over the world.
Two-dimensional materials and their potential
Graphene was the first two-dimensional material; effectively a sheet of material, only one atom thick, but very large in the other two directions. Once it was realised this could exist, scientists began to wonder: 1) What other materials could be made to be just a few atoms thick? And 2) If such materials could exist what new properties might be discovered?
For example, we now know boron nitride is very similar to graphene except that half the carbon atoms are replaced with boron and half with nitrogen. While graphene is an almost perfect conductor of electricity, boron nitride does not conduct at all. This can be very useful, for example when making a fast electrical switch. Other materials can be superconductors or semiconductors and are being used to make more efficient light emitting diodes or better sensors.
Imagining the unimaginable
Personally, in my research we have just published a paper about being able to image things that we were previously unable to. In layman’s terms, when we want to image the atomic structure of any sample, maybe a tiny piece of metal in the electron microscope we usually have to put in into a vacuum – this can change the structure we are trying to look at – even for metal.
As an analogy, consider looking at a prune (dehydrated in vacuum) when you were trying to image the original plum (the fruit’s native state). We have used graphene sheets, separated by boron nitride walls to create a protective bubble of liquid for the sample. This “graphene liquid cell technology” we have developed allows us to retain the sample’s structure while still performing the analysis of the atoms that we require.
Essentially, the graphene acts as a perfect window, protecting the material and maintaining the environment but allowing us to probe the structure.
Promoting science education
I perform voluntary roles with a number of charitable organisations that promote material science and microscopy. One of these is the Worshipful Company of Armourers and Brasiers, which I first came across when I was an undergraduate.
I was fortunate to win one of their scholarships which gave me the opportunity to work for an aluminium company (Alcan) during my vacations. This was a lot of fun and also a great experience. The Worshipful Company of Armourers and Brasiers name sounds intimidating and the Armourers Hall, where they are based, is indeed very grand; full of polished armour and royal crests.
A few years after I finished at Oxford they sent me an email asking how they could better communicate with their alumni. I don’t think they were expecting the three-page stinging critique I sent back. However, they wrote back inviting me to get more involved if I was going to be so opinionated, and I have continued ever since!
The Company does a great deal to financially support science education (especially material science) at all stages from primary to postgraduate, as well as to support and promote UK materials science companies. Through the Armourers I’ve made some great friends and connections with people I would otherwise never have had the opportunity to meet, and they are great sources of impartial advice.
Advice for girls who are interested in finding out more about working in science
For those just starting out I’d advise trying not to cut off your options at GCSE stage by only studying one science. Next, I’d recommend considering your A-level stage subjects carefully and looking at the subjects needed for university level courses – often at least two subjects are required.
Maths is hugely important if you are going on to study science. I did maths, physics, chemistry and art but when I got to university wished that I have covered at least some of the Further Maths syllabus. I definitely didn’t need the art to get to university, although I wonder if the art helped me in a less direct way as microscopy is mostly interpreting information from pretty pictures!
I always have several projects on the go but one we are currently investigating some new 2D materials that appear to behave differently to others we have investigated – all I need to do now is find out how to make the atoms stay still long enough to have their picture taken!