July 23, 2011

by Benjamin White

Two Ohio University physics students can say they are Berliners this summer. Third-year graduate student Heath Kersell and senior undergraduate physics major Vincent Roberts will help some of the best scientists in condensed matter physics conduct their research at Humboldt University on the east side of Germany's capitol.

Though both will work at the Institute of Physics at Humboldt, they will work in different areas because of their expertise and specializations. Kersell, a group member of NQPI’s Saw Wai-Hla, plans to work mostly in scanning tunneling microscopy (STM) to finish one of his Ph.D. projects dealing with surface phenomena. Roberts, who has yet to pick a specialization but plans to enter the field of medical physics, will also work with STMs while spending the majority of his time at BESSY II, a giant ring-shaped laboratory which produces rare, ultra bright photon beams from fast-moving electrons.

“I feel like many of the undergrads don’t get a chance to go abroad very often,” Roberts said. “It’s a much better opportunity to go out and visit other labs.”

The STM laboratories at Humboldt use varying temperatures – a big change from OU’s equipment, which operates at low temperatures. The extreme cold (4.2 to 75 Kelvin) helps to slow atoms down in order to better see them, but experiments at such low temperatures show little about applications in real-world situations. Humboldt’s researchers work more on application, which requires experiments conducted near room temperature. Both Kersell and Roberts also say the lab’s software is unique and its staff more laid-back.

“It’s more of a relaxed feel,” Roberts said. “It’s relaxed but the Germans are very efficient while they’re working. It’s kind of give and take.”

Kersell explained that one possible application of the work in his group is to improve solar cells. Currently, solar cells work by absorbing light, which excites electrons used to generate electricity. Unfortunately, the efficiency of solar cells rarely exceeds 30 percent.

“Scientists are trying to improve the efficiency,” he explained. “They’re making thin films, where you have one layer of some material that is able to absorb light in a certain way.”

Engineers can stack these layers upon each other to maximize efficiency and absorb most of the light spectrum. One type of thin film solar cell has been designed which absorbs ultraviolet light while remaining transparent. These solar cell films could be placed over or incorporated into windows.

“You could fill in all sorts of niche applications with these types of solar cell films,” Kersell said.

Roberts and Kersell join fellow Bobcat Andrew Dilullo, a fourth-year Ph.D. student, in Berlin this summer. Dilullo is working at the Free University on the west side of Berlin. All three participated in NQPI’s SPIRE workshop, which featured half-hour talks from researchers at OU, Hamburg University and the University of Buenos Aires in Argentina. The SPIRE workshop took place in nearby Hamburg from June 29th to July 1st. All three students are set to return to Athens at the start of fall quarter.