Recently there has been a lot of news on graphene being the current ‘wonder material’, but after the conversation I had with Mr Joe Spencer about his research into nano-structures, I might be putting my bets elsewhere.

His specific research involves studying the properties of nano-wires, which can be imagined as a regular cable scaled down to a few billionths of a metre in diameter (ok so not exactly like a regular cable). Here, the plastic insulator is replaced by a carbon nano-tube, which, as Joe explains, is “like a straw of carbon”, and the metal conductor in the centre either remains as a metal, or is replaced by a semi-conductor like silicon.  One thing that struck me as a challenge was actually making these in the first place, but he explains that it is surprisingly straightforward. He tells me that you just get the nano-tubes and the material you want to put inside them, grind them up using a pestle and mortar similar to one you have in the kitchen and you heat two substances up. He tells me that “Nanotubes melt at about 1200⁰C so as long as the material I want to use melts at less than that, the one I use is called mercury telluride, you can put them in the oven and the mercury telluride melts down but the nano-tubes don’t. So by a process called capillary action, this is the same process as the meniscus on a straw, the capillary action pulls the metal into the nano-tube, and when you cool it down, the material recrystallizes again but because it now inside the nano-tube… the atoms have to bond slightly differently when they recrystallize, which is what causes the new material to be made”. Seems pretty straightforward. We then move on to the less straight forward topic of Raman Spectroscopy (no relation to the noodle… I’m a student, I think about these things).

He tells me the term Raman Spectroscopy is “a fancy way of saying use light to look at materials, to understand properties about them”. Here, you fire laser light at the thing you want to look at to make them vibrate. You then look at the light that has been scattered off the sample. He tells me that by looking at this light, you can get information about the energy or type of vibration of the sample, as he phrases it “if you know anything about the vibrations, you can make guesses about the properties of the material, kind of like if you were to flick a piece of glass it would make a ‘tinging’ sound or a piece of wood it would make a ‘thunk’ sound, you can guess information about the material based on the vibrations produced”. In his research, Joe uses this technique to investigate the electronic properties of the material, so if you want to make electronic components with these materials, this is obviously pretty useful information to have. As it turns out, Raman Spectroscopy actually ends up being a pretty useful way of finding different things out, as he tells me that for 2-D materials (things like graphene, ok it’s still pretty cool) “you might be able to guess if it has superconductivity properties, or try and make a sample superconducting, which would be very awesome”. He later tells me that it can be used to find fraudulent pieces of artwork. Useful stuff.

As it turns out, these electrical properties that Joe is investigating could lend these nano-wires to some very useful applications: “You’d want to engineer what we’re making into something called a transistor, which is the underpinning technology behind mobile technology in the 21^st century” so by making these transistors smaller and smaller, you can get ever-more powerful computers as you can fit more of these into the same space. He tells me “at the moment I think Intel are working on the 5nm – 7nm range, now I’m making the wire that you could turn into a transistor that’s about 0.5 nm, so about a factor of 10 smaller, so you’d be able to fit 100 times as many in the same area”.

So with such a direct application to technology already at our fingertips, maybe with a bit more research, these nano-wires will give our next technological leap.

Max