Two ECE graduate students earn Presidential Fellowships

Two Electrical and Computer Engineering (ECE) scholars won Presidential Fellowships from The Ohio State University Graduate School this semester for their work in materials research.

The fellowship provides winners the opportunity and funds to devote full-time efforts to their dissertation research.

Vice Provost for Graduate Studies and Dean of the Graduate School, Alicia L. Bertone, said the fellowship is considered the most competitive and prestigious scholarly recognition offered at the university.

First Presidential Fellow, Seunghyun Lee, is currently a Ph.D. student under advisor and ECE Professor Sanjay Krishna.

“I am absolutely honored,” Lee said. “I strongly believe that this fellowship will play a huge role in my Ph.D. research and my future careers as a buckeye, and also allows me to have additional educational opportunities.”

Lee is developing low-noise avalanche photodiodes (APDs) with III-V compound semiconductor materials as a receiver part for eye-safe Light Detection and Ranging (LiDAR) applications.

“Eye-safe LiDAR technology has been a rapidly growing, ‘new way of looking at the world,’ technology landscape used for improving one's life quality, with non-visible and non-disrupt methods," he said.

Lee said the technology has applications within many other fields, such as autonomous driving, industry automation, gas monitoring, security, and safety.

By expanding the wavelength of the LiDAR systems, he said, a high-performance and low-cost receiver is needed. He is working to advance the materials and device capabilities into new territories, beyond current commercial capabilities.

“Our recent results, with AlGaAsSb materials on InP substrates, have demonstrated the lowest avalanche noise that an APD can theoretically achieve," he said.

Looking back, Lee feels lucky to have worked alongside Krishna for his Ph.D. journey.

"He is one of the renowned experts and has massive experience in the infrared detector field," he said. “Just talking with him every day makes me improve my knowledge and come up with novel ideas for my research. Our lab dynamics are also amazing. Their tremendous help has contributed to my research progress.”

Ironically, second ECE Presidential Fellowship winner Nidhin Kalarickal said he originally had no plans for pursuing a Ph.D.

“In fact, it was a bit of a late decision I took in the final year of my Master’s program,” he said. “Looking back, I am really happy that I chose this path, as the four years at Ohio State have been immensely rewarding.”

Kalarickal is researching ultra-wide band gap semiconductor gallium oxide, which has gained a lot of attention in the last decade for its applications in power switching and high-frequency power amplification.

“The power semiconductor device market is slowly moving toward wide band gap semiconductors. There is just no stopping it,” Kalarickal said. “Wide band gap semiconductor devices simply offer much lower power losses and faster switching compared to Silicon devices.”

This paradigm shift started with the development of wide band gap semiconductors like SiC and GaN in the 1990s and 2000s, he said, but recently several new candidates have emerged, and among those Gallium oxide is the most promising. In his research work, Kalarickal currently focusses on lateral gallium oxide transistors to study and improve transport and breakdown properties using heterostructure and electrostatic engineering. 

“We were able to achieve some remarkable results during the course of my work and we recently demonstrated the highest power figure of merit ever reported in a gallium oxide transistor,” he said.

Kalarickal said his advisor, ECE Professor Siddharth Rajan, has vast experience in the field of wide band gap semiconductors, and learning from him was very important.

“My lab is also very vibrant, and the discussions and exchanges with my lab mates have also contributed immensely toward my progress,” he said.

Both fellowship winners said they plan to focus on their research over the next year. They are also invited to attend the 2022 Ohio State Graduate School’s Annual Award Ceremony.

After graduation, Lee said he hopes to remain academia.

"Becoming a professor is something that I always want to do," he said. "However, I am also open to other options like industry and national labs."

Kalarickal said he has made no decisions for his after-graduation plans but hopes to see where the next year leads him.