This is a guest post from Mo Beshr, an undergraduate student at TU Dublin who’ll soon be starting the final year of his Science with Nanotechnology degree. As part of his third year programme, Mo spent six months — from March until August — in our group. [Note to group: we really need to update our website.] Mo’s thoughts on his internship are below. The best of luck with your final year, Mo!
I knew from before even starting university that I wanted to pursue a career in research as it’s been a long-time dream of mine to make a difference in the world — what better way is there than being on the forefront of science discovering something new every day! All students in my course were given the opportunity to carry out their placement in Ireland or abroad through the Erasmus programme. It was always a goal of mine to travel abroad and experience what it would be like to live independently. So once my supervisor at TU Dublin approached me about placement opportunities, I made it clear to him that I was keen to travel abroad.
I was offered countless research opportunities in various universities across Europe such as Germany, Switzerland and France. I’m not much of a languages guy, however, so I thought I’d give living in Nottingham in England a go; sure, they’re our neighbours from across the pond. But if we’re going to be serious, I immediately jumped at the idea of carrying out my placement in the University of Nottingham as I knew a lot about it through watching Sixty Symbols, Numberphile, and Periodic Videos on YouTube, which are channels that include videos on various topics in science explained by staff members of the university. As well as that, I had known of the great work carried out by the Nanoscience Group at the University and I was very excited to see how all that I had studied as a Nanoscience undergrad was applied. Thankfully I was accepted to carry out my work placement in the University of Nottingham working directly with the Nanoscience Group under the supervision of Professor Philip Moriarty between March and August 2019.
My work was focused on the use of ultrahigh vacuum, low temperature ( 5 K and 77 K) scanning tunnelling microscopy (STM) for atomic resolution imaging of metal and semiconductor surfaces, spectroscopy and manipulation of single atoms and molecules. As you can imagine, going from being a goofy student who attended a handful of lectures everyday to being thrown into the big bad world of research was quite daunting. However, with some time and excellent help and advice by the PhD researchers I worked with and my supervisor I got into the swing of things quickly.
Initially, the toughest tasks were understanding how the STM system I would be using operated and how to analyse STM images and spectra. During my initial time in Nottingham I worked with a PhD researcher named Alex Allen on his project, which involved taking scanning tunnelling spectra (STS) of a C60/ Ag(100) sample using the Createc low temperature STM system. When I had first arrived, a sample of C60/Ag(100) had already been inside the Createc STM chamber and only ever removed for annealing and deposition purposes. During one of our weekly meetings, Phil noticed there were porphyrin contaminants on our sample and in order to fix this we had to remove the sample first from the STM and then from the ultrahigh vacuum chamber. While doing this we were, of course, always observing the movements of the STM tip using the live video from the camera. We then replaced the sample.
Once cleaning of the sample had been completed (by sputtering with ions and subsequent annealing), we would bring the sample back into the STM chamber and scan it in order to make sure it was clean and had an atomically flat surface; on the final sputter-anneal cycle, we achieved atomic resolution. Deposition of the desired molecules would then take place. The deposition process involved placing the sample over a crucible of C60. The crucible was then heated up with a high current which in turn sublimes the buckminsterfullerene molecules, thus allowing for the molecules to impinge on the surface of the sample. Once deposition was complete, we collected liquid nitrogen — following my health and safety induction — and then pumped it through the manipulator arm. This was done in order to cool the sample and control just how the fullerene molecules crystallised on the surface.
Finally, the sample was returned to the STM and scanning commenced once again. The cryostat surrounding the STM was regularly filled with liquid nitrogen, which keeps the sample cooled throughout the scans…
In quite a few cases the scans were quite blurry or appeared smeared due to the STM tip being in a bad state. Sometimes the tip wasn’t atomically sharp and/or add more than one molecule on its apex, leading to multiple tunnelling current centres and thus “blurring” the image. In that case, a method known technically as, err, “crashing” was implemented — a clean area was found, and the tip was pushed into the surface to modify its apex. Once a tip had been “sharpened” and clear images were produced, we could carry out scanning tunnelling spectroscopy (STS) of the surface at any specific point. The tip would be positioned above a molecule. The bias was then varied, and the tunnelling current was recorded, giving a plot of the current-voltage characteristic for a single molecule. Differentiating the I(V) spectrum gives us information on the density of states of the molecules.
As well as gaining valuable experience in operating STM systems, I also obtained training in so-called “soft” skills. Literature review topics were assigned to me prior to carrying out any experimental work so I would have a better understanding of the topic of investigation. This involved me writing a report summarising the literature on that topic. The reviews were an excellent opportunity for me to improve my academic writing skills; with every review I could see improvement, and this prepared me very well for my end-of-placement report. After each literature review, I presented what I had found during group meetings, which was very intimidating as I had never given a presentation before! However, I improved with every presentation and the practice gave me great confidence when I returned to Ireland to present my work placement experience to my peers and lecturers.
Completing my work placement with the Nanoscience Group at Nottingham has let me apply what I have learned in my three years as an undergraduate student and really opened my eyes to a future in research and academia. I now understand what it takes to be a researcher and I believe that I am now capable of pursuing my dream of becoming a researcher and hopefully to make a positive impact in the world of science. I hope this blog inspires other students like me to consider research as a future career path, as there is truly so much still out there to learn and find out. One tends to learn something new every day, and you realise that you are indeed on the frontline of science.