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Aabha Rathee/MEDILL
Prof. Siva Sivananthan at the UIC microphysics department. Sivananthan is working on commercializing new technology in solar cell fabrication.
After brush with war, scientist joins renewable energy battle
by Aabha Rathee
March 10, 2011
The Cd-Te/Si cell
• Uses II-VI (cadmium-telluride) semiconductor material on silicon, which is cheaper than using III-V on germanium• The electro-optical properties have been made relatively insensitive to structural defects and lattice mismatches by using an arsenic interfacial layer
• Will be used in concentrated photovoltaics, with theoretical efficiencies of approximately 40 percent
In the summer of 1983, the microphysics pioneer at the University of Illinois at Chicago was preparing to take his preliminary examination at the university to begin his doctoral dissertation. That’s when he heard that riots had begun back home in Sri Lanka – the start of a civil war that only ended in 2009.
Sivananthan wanted to head back right away. He had tried and failed to get in touch with his wife who was in the northern part of the country, the center of the violence. “We had not managed to make any connection with her, I didn’t know if she was hiding, where she was,” he said.
James Garland, Sivananthan’s professor at the university at the time and now retired, though, told him leaving would be futile. “Jim said to me: ‘Where are you going to go? You’ll be trapped. It’s not going to help. It’s easier for you to do things from here,’” Sivananthan said.
So he stayed and took the examinations, and as it turned out, heard right after that his wife was safe. Garland said the decision to stay probably turned out to be a make-or-break one for Sivananthan.
He was one of the first doctoral students of Prof. Jean-Pierre Faurie in the lab that was just starting to grow. The university lab of microphysics, the study of material at a microscopic level, was focused on doing further research in mercury cadmium telluride for infrared and later solar technologies.
And when Faurie returned to France, Sivananthan, who had completed his doctoral thesis by then, was asked to take charge. “Siva sort of inherited the microphysics laboratory. Had he started a year later, it might have been very different,” Garland said.
Sivananthan credits Garland for helping him make that decision. “It had a huge impact, having someone ... It looks like a small thing, but the impact it has on somebody’s life is very strong,” he said.
The decision to stay changed Sivananthan’s career track, but it also meant it was going to be a different life for his family. As the violence in Sri Lanka grew, his wife came to the Chicago area, which became their home. They raised their two daughters in Naperville.
In 1998, Sivananthan, began to commercialize his research through a company called EPIR Technologies Inc. Family photographs line up his office desk in the company office in Bolingbrook. But inside the laboratories, work is on to develop a new material in solar cell technology that Sivananthan hopes will be the next big thing in expanding the use of this underdeveloped form of energy.
Sivananthan’s cadmium-telluride on silicon material (explained in accompanying box) has been developed to adapt the current existing silicon-cell technology to improve its efficiency without raising the cost.
“The key thing here is adaptation. We’re trying to work with the technology that is currently dominating the market – silicon cells are 80 percent of the solar cell market,” he said.
But back in the ‘80s, Sivananthan had stayed on to expand on his first project in molecular beam epitaxial, a method of depositing single crystals. The first product of his research was the fabrication of a mercury-cadmium-tellurium material that could be used to make infrared and night-vision detector devices.
In 1998, continuing with further research single-crystal research at the UIC microphysics laboratory of which he is now the director, Sivananthan also started a company to commercialize the infrared technology and bagged contracts from the U.S. Department of Defense.
“I started EPIR to provide research and development for mercury-cadmium-telluride technology, and to eventually become a material manufacturer for infrared,” Sivananthan said. “I didn’t like how the market was structured, and also, once the military comes into the picture, all research can’t be done by a university lab."
The next breakthrough was the synthesis of cadmium-telluride on silicon, according to Sivananthan. “From 1997 to 2007 I worked with my students rigorously to research this. Until 2007, our focus was to see how we can synthesize single-crystal cadmium-telluride on a silicon substrate. By 2007 I realized we had done enough research and that we were ready for the next level. That’s when we started to initiate the program for solar cells,” he said.
The solar cell program has received funding from the U.S. Department of Energy to develop it further, but Sivananthan is working on getting commercial backing. “We have the proof of concept, but the manufacturing process needs to be optimized. It’s more of an engineering issue moving forward, not much of a science issue. So we’re extremely optimistic.”
That optimism would be for a reason, but Sivananthan said it is a characteristic he has grown up with: “My parents are teachers and the confidence level I was given was very strong, ‘You can do it,’ I was told all the time.”
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