Laser Focus on Electron Microscopes Helps Doctoral Student Win First Fellowship

A doctoral candidate will receive $20,000 as part of a new annual fellowship available to Clemson University graduate students who use electron microscopes that magnify with atomic resolution.

Yunsong Zhao, who is pursuing a doctoral degree in electrical and computer engineering, is the first recipient of the Hitachi High Technologies America Electron Microscopy Annual Fellowship.

The fellowship strengthens ties in a longstanding partnership that has resulted in a cutting-edge Clemson University lab packed with Hitachi microscopes.

Hitachi High Technologies America Inc. has pledged $100,000 over five years to the fellowship with an option to extend the program. The fellowship is worth $20,000 to each recipient, and the money comes with no restrictions.

“I feel great, very honored,” Zhao said. “The most exciting thing is that my research is recognized by others. It’s useful. It’s not only equations and formulas. It can really change the lives of others.”

Zhao’s work focuses on making semiconductor lasers powerful while maintaining good beam quality for use in research and industry.

Fellowships are open to College of Engineering and Science graduate students who use electron microcopy in their studies. The microscopes use electrons to magnify specimens at a much higher resolution than optical microscopes.

The super-magnification has a wide range of uses in research and industry. For example, electron microscopes are used for quality control, computer-chip manufacturing and analyzing viruses.

Zhao does much of his work in Clemson’s Electron Microscopy Laboratory, which is housed within the Advanced Materials Research Laboratory in Anderson.

All eight of the lab’s electron microscopes are made by Hitachi High-Technologies Corp. in Japan. Hitachi High Technologies America has a senior service engineer on site at the lab to maintain the equipment.

Another Hitachi electron microscope is in Jordan Hall on Clemson’s main campus, and one is located at the Warren Lasch Conservation Center in Charleston.

Hitachi High Technologies America has long had an active K-12 outreach program focused on science, technology, engineering and mathematics (STEM). The fellowship at Clemson is the company’s first STEM-outreach effort into higher education.

“We are so proud and pleased with our relationship with Clemson,” said Phil Bryson, vice president and general manager of the Nanotechnology Systems Division at Hitachi High Technologies America. “The fellowship was a natural extension of our partnership.”

Doug Griffith, the company’s southeastern sales manager, said the lab serves as a model for the rest of the country, attracting the interest of other universities, from Harvard to Georgia Tech.

The floors under the microscopes are on slabs that go down 26 feet to cancel vibration and acoustic noise.

“If you want to build a lab, you want to come here and visit first,” Griffith said. “I would be remiss if I did not mention Dr. Chris Przirembel, past vice president of research, as he was the man who conceived and built the AMRL and the former director of the lab, Dr. Joan Hudson. Together they had the vision that resulted in this world-class electron microscopy facility.”

Experts use ion milling systems to prepare samples that can range from silicon to copper. One system can shave samples with amazing precision — several atomic layers at a time.

“This lab has some of the best sample-prep experts in the world,” Bryson said.

Hitachi officials said that when they began searching for ways to further support higher education they met with Larry Dooley, Clemson’s vice president for research. Dooley had the idea of creating a fellowship at the graduate level, where it would have the most impact.

“Each fellowship is enough money to pay for a full year of graduate school,” he said. “We’re extremely grateful for Hitachi’s support. We are also proud of Yunsong. He was a unanimous choice to be the first fellow.”

Lin Zhu, who is Zhao’s adviser, said he is an asset to his research group and a “personable individual” who will be a good teacher. Zhao has published six journal papers and two conference papers, which is highly productive for a researcher this early in his career.

“Mr. Zhao is the most outstanding graduate student I have known at Clemson University,” said Zhu, who is an associate professor in the Holcombe Department of Electrical and Computer Engineering.

Semiconductor lasers are small compared to other lasers — usually a few millimeters wide — and are used in laser pointers, CD-ROMS and optical telecommunication networks, Zhao said.

But making them more powerful while maintaining good beam quality comes with challenges, he said.

“When semiconductor lasers are pushed to a very high power, you cannot maintain a good beam quality in a conventional laser design,” Zhao said. “The laser will degrade.”

If the challenges can be overcome, high-power and high-brightness semiconductor lasers can be used as a pump laser for solid-state lasers to produce a much higher power laser, he said.

“That can be used in industrial production,” Zhao said. “It could be used to cut and drill holes.”

Zhao uses electron microscopes to make sure that “fine optical gratings” meet design requirements.

He also uses electron microscopes to monitor the etching process during fabrication of his laser diodes. Those etchings need to be accurate within about 50 nanometers. One nanometer is one-billionth of a meter.

Zhao’s research is supported by the Army Research Office.

Laxmikant Saraf, director of the Electron Microscopy Laboratory, said the lab is used by faculty and students about half the time and by industry about half the time.

“The fellowship helps complete the picture by bringing in more students,” Saraf said.

Tanju Karanfil, associate dean for research and development in the College of Engineering and Science, said he expects the fellowship to help recruit top-quality students.

“We’re extremely grateful for the support from Hitachi High Technologies America,” he said. “The fellowship will enhance Clemson’s already strong reputation in electron microscopy and help advance a field rapidly growing in importance to industry.”

Bryson and Griffith recently visited the Electron Microscopy Lab, where they presented Zhao with his fellowship. Nadim Aziz, interim dean of Clemson’s Graduate School, joined them in congratulating Zhao.

“Yunsong is one of those excellent, highly motivated students that sets Clemson apart,” Aziz said. “We greatly appreciate Hitachi High Technologies America’s support for our graduate students.”

Added Griffith: “There’s a lot of history here, and a lot of future. We’re very proud of it.”