My Summer Research: Saving the World

OK, not quite. But I did contribute a tiny bit to my research group’s efforts to develop a new type of solar energy converter that could make a big difference in the way we create and consume energy.

I spent most of this summer working in a multidisciplinary research group under the Stanford EE Department’s Research Experience for Undergrads (REU) program. Our work focused on a new solar energy harvesting concept called Photon Enhanced Thermionic Emission (PETE) and dreamed up by Nick Melosh, a MatSci professor at Stanford. I can’t go too much into the details now, since the seminal paper is yet to be published, but PETE holds a lot of potential as a novel source of low-cost renewable energy because unlike traditional PV (solar) cells, which quickly lose efficiency at high temperatures, PETE actually gains efficiency with increasing temperature, feeding off the heightened thermal energy to aid photoemission. As a result, we can combine the PETE device with a solar thermal converter––which, as a heat engine, can only run efficiently at elevated temperatures––and realize some absurdly high theoretical conversion efficiencies. For those familiar with solar cell operation, PETE can beat the Shockley-Queisser limit by taking advantage of below-bandgap photons and heat energy from hot-carrier thermalization.

Anyway, it turns out PETE, as well as many other optoelectronic devices, can get a pretty significant photoemission efficiency boost from the use of semiconductor nanostructures, like nanowires. For that reason, I spent 10 weeks this summer building a Monte Carlo simulation to characterize electron dynamics in nanowires, to help us better understand how electrons behave under various material conditions at nanoscale dimensions. My post-doc mentor, Igor, created the basic framework and helped me build and test the simulation. I ended up with some pretty cool results. I reproduced the negative differential resistance phenomenon in GaAs and matched the experimental scattering rate data surprisingly accurately. The graphic below is a visualization (created in Mathematica) of a single electron trajectory in a GaAs nanowire.

The lucky electron is injected at the solid black ball and bounces around for a while under the influence of probabilistic scattering mechanisms, gaining kinetic energy (shown as a black-to-red gradient), and finally escapes into free space at the solid red ball.

The lucky electron is injected at the solid black ball and bounces around for a while under the influence of probabilistic scattering mechanisms, gaining kinetic energy (shown as a black-to-red gradient), and finally escapes into free space at the solid red ball.

I got really lucky this summer, with a great mentor who wanted me to learn and a meaningful project in a high-potential field that might have shifted my entire academic and career trajectory toward grad school and solar energy research. That said, I’m still exploring other interests, and entrepreneurship still holds a fundamental appeal to me, so who knows where that combination will lead me? At the end of the summer, I got to give a couple presentations, one to my lab group and one to the entire REU program, advisors, and guests. I had a good time with both, and I’m excited to keep working on the PETE project as the new school year starts.

One of the greatest things about research, especially engineering research, is the flexibility that you often have with your work environment. Maybe it’s because they didn’t want to waste precious desk space in Allen on me, but I ended up working from my dorm, from the library, and from just about anywhere else on campus with an internet connection (and at Stanford, that’s pretty much everywhere). I could, and often did, wake up at 10PM and still get more done than a 9-to-5er by working on my own schedule, at times when I was most efficient, including sometimes late into the night. The 8-hour workday and Monday-to-Friday workweek simply didn’t exist––I might work 13 hours one day, 6 the next, a few hours here and there on a Saturday––but when something needed to be done, I got it done. If a friend needed a 4th man to fill out a beach volleyball team, I was there. And I still found time to read a couple books, go to the beach with friends, keep up my running, and have the summer of a lifetime. And although the task may be harder, the prospect of starting my own company holds a similar allure. After all, when you truly care about and believe in the meaning of your work, why wouldn’t you want to spend as much time with it as it takes to succeed?

Thanks for reading.

-Joel

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One thought on “My Summer Research: Saving the World

  1. […] but I know I’ve been using a similar strategy for a long time. I’ll work on my research to avoid writing a paper, or make a flyer for ASES to skirt a trip to the post office, or plan out […]

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