This article is part of a larger project by The Michigan Daily to examine University of Michigan research trends by analyzing academic paper citations. The Michigan Daily spoke with Stephen Forrest, Peter A. Franken Distinguished University Professor of Engineering, Paul G. Goebel Professor of Engineering and one of the top ten most cited researchers connected to the University, to discuss his career and research. Read the other stories here.
Though he received his master’s and doctoral degrees from the University of Michigan and returned to the institution in 2006 as a professor of electrical engineering, Stephen Forrest’s path to academia began at a private company. In an interview with The Michigan Daily, Forrest said his career took him first into the field of fiber optics at Bell Laboratories, a research and development company famous for groundbreaking technology discoveries.
“I started out in industry, as many of my colleagues have, after graduate school,” Forrest said. “My field of study was pure physics, but I got involved in optical fiber, fiber optic communications. I went to Bell Labs at the time when optical communications was just emerging, and I started to work on photodetectors for fiber optics.”
Fiber optic lines are thin strands of glass that transmit data in the form of light. Forrest said his work at Bell Labs led him to help develop photodetectors that could convert light signals from the lines into electrical signals that provide digital information in binary, a string of ones and zeros that forms the base for all computing.
“Every fiber optic cable has a light source on one end that’s putting out ones and zeros — basically, light on, light off — and that travels down to fiber, and then it gets to the end of the fiber, where it has to be converted back into electrical ones and zeros,” Forrest said. “So that’s where I started, it was very exciting and fascinating. And we made the photodetectors that are now at the end of every optical fiber in the world.”
Even though his work on photodetectors contributed significantly to the field, Forrest was drawn back into academia in the hopes he would be able to follow his own research interests. After teaching at the University of Southern California and Princeton University, Forrest found himself back at the University of Michigan as the vice president for research.
Stepping down from his administrative position in 2014, Forrest now teaches in the Electrical Engineering and Computer Science Department. He said his current research focuses on semiconductors, compounds that can selectively conduct electricity under certain conditions, and their light-related uses.
“I’m very interested in semiconductors, semiconductor materials and their applications, particularly having to do with photonics — light-emitting devices, detectors, solar cells, OLEDs, thermal photovoltaic cells for converting heat to electricity as a form of retrieval of energy from thermal storage, etcetera,” Forrest said. “So just almost anything having to do with semiconductors and light.”
Over the course of his career, both in and out of academic settings, Forrest has made important contributions to his field of research. He cited photodetectors from his work at Bell Labs as one of his most valued innovations, but he also noted his work on organic light-emitting diodes has made its way into the pockets and homes of countless users.
OLEDs are layered materials that emit light in response to changes in electricity, producing the images displayed on many cell phones and some modern televisions. Forrest said the ongoing implementation of OLEDs into more devices stemmed from work done by his team.
“The other is organic vitamin D diodes used in all these displays,” Forrest said. “I’m sure you have a cell phone in your pocket that has an OLED display on it. Those materials and devices came directly from my lab.”
Forrest’s work has earned him approximately 190,000 citations on Google Scholar as of publication, which he attributes to the widespread digital applications photodiodes and OLEDs have in today’s digital age.
“I think the work has made a lot of practical impact,” Forrest said. “If you make photodiodes and they’re found at the end of every optical fiber, people are going to be referring to that work. The other thing that we have done a lot of work in is organic LEDs. So our work in organic LEDs have resulted in every OLED display out there, and there’s about 3 billion of them. There are teams of scientists working on stuff and engineers working on stuff that follow our work, and therefore they refer back to it.”
The academic world often measures success by number of citations, with many institutions taking it into account when evaluating professors for tenure and hiring new faculty. Forrest said some fields are more niche than others and may not accrue as many citations, but he felt this should not diminish from researchers’ work.
“One should not confuse that with actual impact,” Forrest said. “I think that’s something that academics very often do, that they think if they have a lot of citations, that there’s a lot of impact. Not necessarily. As a matter of fact, in some fields, the citation levels are quite low, but the impact can be quite high.”
Throughout his career and across institutions, Forrest has worked with countless other researchers to develop new ideas. He said being willing to share ideas, communicate with others and work with a team were key to becoming a successful researcher.
“You have to recognize that making advances today is a very interdisciplinary activity,” Forrest said. “You need to have people with different perspectives and different skills than you have, different knowledge bases. And if you’re willing to do that, and then to share the credit quite evenly, then it’s pretty easy to work with people, to collaborate.”
Forrest has found success in collaborating with Mark Thompson, professor of chemical engineering at the University of Southern California, for more than 30 years, which he said was his longest and strongest relationship in the academic community.
“We have worked together on OLEDs, on solar cells, on everything organic,” Forrest said. “We’ve worked on starting companies together. That’s fairly unusual in academia to have such a long term close partnership with another group, but we’ve managed to do that seamlessly for 30 years now.”
In a community that continually asks questions and attempts to solve new problems, Forrest said knowing which questions are worth pursuing was a valuable skill researchers should learn to develop.
“Having a good nose for problems to work on, problems that have impact larger than just for other academics, but for society at large, that’s called scientific taste,” Forrest said. “Having good scientific taste means picking your problems carefully and don’t get sidetracked into areas that are just sort of marginal. That’s what separates good researchers from average ones, which is being able to very carefully choose problems with an open horizon that lead to that kind of open inquiry and perhaps significant impact on society.”
Daily News Editor Marissa Corsi can be reached atmacorsi@umich.edu.
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