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NAMBE 2017 Top Student Paper Awards

After hours of research toward potentially creating the next breakthrough in engineering, two students from The Ohio State University walked away with top Outstanding Student Paper Awards at the Texas-based North American Conference on Molecular Beam Epitaxy (NAMBE) back in October.

Choong Hee Lee is a PhD candidate in electrical and computer engineering (ECE) at Ohio State, under the guidance of associate professor Siddharth Rajan; and Brelon May is a PhD candidate in material science engineering (MSE), overseen by Roberto Myers, a professor in ECE and MSE.

Choong Hee LeeChoong Hee Lee

In the winning research paper, “Large-area SnSe2/GaN heterojunction diodes grown by molecular beam epitaxy,” Lee and his fellow authors discuss the process of creating powerful heterojunction bipolar transistors (HBT), a radio frequency application, through the integration of two-dimensional (SnSe2) and three-dimensional (III-Nitrides) material diodes, in a process called molecular beam epitaxy, which allows for precise control of materials at the atomic level.

Such research has the ultimate goal of advancing the speed of data transfer for next-generation internet and other applications.

“Making diodes is the first step to creating a new class of devices that combine 2D materials and conventional 3D semiconductors," Lee said. "This paper is about making those diodes."

Lee said several 2D semiconductors have a narrow band gap and GaN has a wider band gap, so combining the two enables new combinations of materials to surpass current technology.

Professor Rajan said the work presented in the NAMBE 2017 conference was an important step toward realizing such combinations. Lee’s project, funded by the Air Force Office of Scientific Research and Northrop Grumman Space Systems, aims to realize next-generation high frequency transistors using such novel combinations of materials.

Overall, Lee said, working under the guidance of Rajan allowed for a great deal of freedom and resources, along with humility and channels for learning new areas of ECE. He said the NAMBE conference, in particular, allowed him to learn a lot more about the growing field of molecular beam epitaxy research.

Lee will complete his dissertation either 2018 spring or fall semester, and hopes to stay in academia and conduct research.

Brelon MayBrelon May

May’s winning paper is titled, “Simultaneous molecular beam epitaxy growth at multiple uniform substrate temperatures,” which explores new methods for creating engineering device materials.

Within the research, May created a four-container substrate holder, which enables the pressure to remain constant within the chamber, while the temperature can be altered. Not only does this speed up the growth process, but once measurements are recorded, it is easier to determine the ideal growth condition.

In this particular paper, May grew MoSe2 and found the perfect growth temperature, around 550 degrees Celsius. Discovering this ideal zone took six hours, where normally it would take multiple days, thus quadrupling the speed of doing material research.

“Somewhere I heard, ‘laziness bred innovation,’” May laughs. “I didn’t want to spend two months. I wanted to do things faster; but we use this to create growth maps of different materials.”

May added that Myers allowed for lots of creative freedom, and was very supportive and helpful as an advisor.

As for NAMBE, since this is May’s favorite conference, he hopes to return in the future, even after he gains his PhD at Ohio State.

“It is my favorite conference because it’s a bunch of people doing the same thing I do, just with different materials,” he said. “It’s always fun to hang around like-minded people.” 

Story by ECE Student PR Writer, Lydia Freudenberg