Improving Solar Cells

improvingsolarcells646.jpg

John Graham, Professor Doyle, Andrew Hansen

CATEGORY: Academics
TYPE: Articles
RELATED PROGRAMS: Physics & Astronomy

By | John Graham ’14
Wooster, Ohio
Physics, Mathematics

“Our method of growing low-temperature amorphous films is a very hot candidate for use in cheap, efficient tandem solar cells.”

Curiosity, a passionate mentor, and a Hawaiian shirt are all you need to dive into physics research at Macalester.

As a junior, I applied to some summer REUs (Research Experience for Undergraduates) and was rewarded with offers for research positions, but ultimately I decided to spend the summer working for Macalester professor Jim Doyle in the Olin-Rice community I know and love.

I worked in Doyle’s Thin Film Laboratory, studying thin (~3000 ångström thickness) germanium films. Germanium (Ge) is a semiconductor located right below silicon on the periodic table and, like its upstairs neighbor, has many applications in modern electronics and solar energy technology. Our method of growing, then baking, low-temperature amorphous films is a promising candidate for use in cheap, efficient tandem solar cells.

It’s relatively easy to grow thin germanium films using magnetron sputtering, our method of deposition, but over the summer I still had to tackle many problems. Temperature stability, heating schedules, and proper interpretation of the data all required many hours of optimization in the baking process. In addition, we had to custom design much of our experimental apparatus and build it ourselves with help from Ken Moffet, our scientific instrumentation specialist.

Easy access to useful facilities and research instruments (such as Mac’s Keck Lab) made for a very productive work environment. Professor Doyle and I hope to publish some of our results this year.

An exciting blend of activities including thinking, planning, designing, building, redesigning, and rebuilding led to a research experience where each day brought new surprises. I found I was well prepared to take on complex tasks in physics experimentation, and able to contribute substantially to the intellectual direction of the work.

PUBLISHED: 10/01/2013