Preparation and spectroscopy of graphene nano-fragments
Tell us about the school where you teach. I’ll be starting my 16th year at Flowing Wells High School in Tucson. I’ve been teaching chemistry, honors chemistry and advanced placement chemistry for the entire time I’ve been there. Describe your project. My research is still in its infancy. Basically we are going to be looking at a compound called graphene. It’s one of the allotropes of carbon, very similar to graphite. It’s an individual layer of graphite, of carbon atoms, arranged in a six-carbon ring. And what I’m eventually going to be looking at once I figure out a method of obtaining something called a quantum dot, which I’ll get to here in a minute, is the electrical properties of the quantum dot and how the electrons in the quantum dot interact with each other, rather than studying just the single electron. So this summer what I’ve been doing is learning a lot of methods to start doing my research, everything from growing graphene via chemical vapor deposition, to transferring it onto various substrates. Troubleshooting a lot of the smaller issues with that has pretty much taken up the entire summer. I’ve also been doing Raman spectroscopy to characterize the quality of the graphene. I’m learning how to adjust and manipulate that, which I will be using when we later start measuring some of the nonlinear properties. We’ll be doing pump-probe measurements which involve adding a certain amount of energy or intensity to a sample, and then take we basically take a picture of it through various phases as the electrons are excited up to one state and then basically fall back to non-excited states. While we’re doing that, we’ll also heat the samples and note how temperature has an effect across the spectrum. Have you been trained in ultrafast laser techniques? Not formally, but I’ve looked over the shoulders of other people in the group. Basically it’s been an awesome experience every day. I’ve learned so much. Everyone in the group is helpful. This is a completely new field to me, which has been exciting to learn about, because my background is in chemistry, not in physics. What is the most fascinating thing you’ve learned? That you can take attosecond pictures of electrons, which is extremely fast, I guess 10 to the minus 18 using ultraviolet light. I’ve been privileged to watch some of the other members of our group do that. It’s also interesting to see how they put together the lasers used in these experiments, and how they later tear them down. Watching this has made me realize research is not just pushing a button and watching something happen, but rather it’s a constant process of solving problems that arise all day, every day, all month, all summer. Did you encounter something unexpected or unpredictable? I would have predicted that at this point I would have my quantum dots. But after the second or third week of looking at it over the summer, I realized that manufacturing them myself was going to be a long process. So we’re trying to see if we can get another group somewhere in the country who oversees this process to send us samples. Why are you interested in quantum dots? The thought is that if we can understand how a smaller quantum dot sample of graphene behaves, we can then begin to understand how electrons move through a larger sheet and thus develop a better understanding of this fascinating material. What are you going to take from your research into your classroom? That basically one’s entire life is a process of acquiring knowledge. And that’s true whether you screw off trying to draw a smiley face with Crayons, versus trying to learn how electrons fit in the Periodic Table, or whether you’re trying to learn about the electrical properties of graphene. The same problem-solving steps are required in all cases. The basic point is that you just can’t quit when something doesn’t work, and that you should get excited about it. How is this program helping you to accomplish your professional goals? First and foremost I’m learning more in the higher end of the science spectrum. It’s not the real dry teaching-development courses, which I guess certain sets of teachers to grow. I’m really happy to have this opportunity to work with all the grad students and my principal investigator. Essentially I’ve gotten to take the role of fulltime student again. It’s brought me back to what it’s like to have someone talking to you while you have no idea what they’re saying, and then having to go back and figure it out. It puts me back in the shoes of my students. So now I can go back and think about some of what I’m saying as I teach, and maybe try to approach it a little differently for certain kids.