Lehigh had a strong presence at the IEEE Photonics Conference (IPC) held during the first week of October 2017 in Lake Buena Vista, Florida. IPC is IEEE’s flagship conference dedicated to the fields of optics and photonics.
Lehigh faculty and students from the Center for Photonics and Nanoelectronics (CPN), the Department of Electrical and Computer Engineering (ECE), and the Department of Material Science and Engineering (MSE) presented nine technical talks.
Filbert J. Bartoli, professor in CPN and ECE, presented and held a panel discussion on the “Grand Challenges of Photonics Research.” Bartoli is currently the division director for the Electrical, Communications and Cyber Systems at National Science Foundation (NSF). Siddha Pimputkar, assistant professor in CPN and MSE, presented on the progress of “Gallium Nitride (GaN) Substrate Growth.” Jonathan J. Wierer, associate professor in CPN and ECE, provided an overview concerning Lehigh’s efforts on “Achieving Ultra-Efficiency in Solid-State Lighting.”
Nelson Tansu’s group presented six technical papers in the conference. Tansu is the Daniel E. '39 and Patricia M. Smith Endowed Chair Professor in CPN and ECE, and he also serves as CPN director. The six talks presented a series of scientific advances in III-nitride materials and devices and their applications to energy efficiency, communications and internet-of-things (IoT) and environmental technologies.
Graduate student Austin M. Slosberg and Eric T. Reid ‘17 gave talks on nanophotonics technologies for GaN-based vertical cavity lasers and tunable diode lasers, respectively. Such devices are the building blocks for IoT, visible light communications and sensing technologies. Reid was the 3rd place recipient of the 2017 David and Lorraine Freed Undergraduate Research Award and is a PhD candidate at University of Michigan, Ann Arbor.
Graduate student Ioannis Fragkos presented on the limiting factors of the rare-earth doped GaN light-emitting diodes, research of which was performed in collaboration with Volkmar Dierolf, physics department chair and CPN member and Yasufumi Fujiwara, professor in materials science and engineering at Osaka University, Japan. Fragkos’ work provides new insights to break the limitation of red-emitting devices, which are applicable in display technologies.
Wei Sun’s talk covered a new class of material called a “digital alloy” whereby the quantum-mechanical properties of nanostructures are used to build “bulk-like” semiconductors with tailored properties. Sun’s key papers on III-nitride digital alloys were published in Nature’s Scientific Reports in July and September 2017. At the conference, Sun extended this work to involve the creation of a digital alloy for deep UV emitters, which are applicable to environmental sensing and water purification. The research is supported by NSF’s Electrical, Communications and Cyber Systems (ECCS) division.
Graduate student Damir Borovac and Chee-Keong Tan ’16G (Ph.D.) presented two new results based on dilute-anion III-nitride semiconductors. Borovac’s work provides new findings on large bandgap bowing in GaN with a minute amount of phosphorous, while Tan showed how the electronic structure of Boron Nitride alloy can be engineered with a small addition of impurities. Such work is considered highly impactful, establishing new directions for III-nitride research, and is supported by NSF’s Division of Material Research. Tan became a tenure-track assistant professor at Clarkson University after graduating from Lehigh in 2016.
The new directions in wide bandgap research will be accelerated by the recently secured Major Research Instrumentation (MRI) grant from NSF to develop a unique reactor to synthesize new materials under extreme conditions. The MRI team includes Tansu; Pimputkar; Wierer; Dierolf; Nicholas C. Strandwitz, assistant professor in MSE; and Renbo Song, CPN’s scientific manager. Specifically, this MRI reactor will be used to produce unconventional III-nitride and oxynitride semiconductors. Such new wide bandgap semiconductors will be transformative in the development of new device technologies with applications in energy efficiency and renewable energy, smart vehicle and power delivery systems, optical communications and IoT.