Christian Berger
PhD (Vijayaraghavan group): condensed matter physics, solid state physics, materials science
Today’s just been a problem with one of the bits of equipment. It's alignment, so you have one substrate, which has say, some gold electrodes on the top, so that's for making electrical contacts. On top of that you want to transfer your graphene which is patterned in a certain way. You want the two layers to align perfectly. In order to align them you have two reference frames, so you have to work out the size of your first reference frame. So you measure out the graphene. And then what’s the size of the other reference frame? And then you do a series of alignment steps to align the two; and at that point you have to be very rigorous, you have to work to sub-micron dimensions. You have to concentrate really hard, and at the same time you've got all these backing pumps going off in the background, people tapping you on the shoulder asking questions. It fries your head a bit.
There are bright yellow lights in the clean room. It's yellow because a white light would expose photosensitive materials and you're wearing a full clean room suit, which means mask, cap, boots, gloves, hood, a whole gown and that'll take like five or six minutes to put on, or take off. And if you want to go to the toilet, you're like, oh I'll just wait another half hour until I finish this process but then you make a mistake, and you're like, oh I'll just wait another half hour and it just drags on to four or five hours.
But if you've managed to pull through the four or five hours and you finally get results and everything lines up, and you've got a device, you then know you've finished your lab work and you can go into your nice comfortable chair, sit down and do some measurements and watch the results come into your laptop. It's a very rewarding process when it all works out.