Creating a safer UV light source, student wins best paper at ISSLED 2017
Yuewei Zhang earned the best paper award at the recent International Symposium on Semiconductor Light Emitting Devices (ISSLED 2017) conference in Banff, Canada, for his research proposal, “Reflective metal/semiconductor tunnel junctions for hole injection in AlGaN UV LEDs.”
His work outlines a way toward producing a high-powered UV bulb without the danger of releasing mercury; like other UV lamps are known to do.
Hazardous waste management organizations typically warn the public about the dangers of disposing and storing compact or linear fluorescent tubes, halide street lamps, halogen, ultraviolet lights and neon lights because they contain trace amounts of mercury. However, the light sources are also important for reducing greenhouse gas emissions, can provide over triple the energy efficiency of incandescent lights, cost less to use, and may last up to 10 times longer than traditional bulbs.
In detail, Zhang said their research focuses on a new structure his team created where charged carriers, particularly the positively charged carriers (holes) that are responsible for light generation in a solid-state semiconductor material, are tunnel-injected through a reflective tunnel-junction structure into the device. This creates an efficient hole injection, thus producing a high-power UV emitter where no mercury is released.
“Basically, using this structure we are already comparable to state-of-the-art devices,” Zhang said. “We can create a pretty efficient UV light source now … It’s completely environmentally friendly, and it’s very compact in size.”
While still testing their work in the lab, the team is hoping to find ways to extract more light from the device to eventually create a real, marketable light bulb for applications in water purifications, air disinfections and others.
Throughout his time in graduate school, Zhang said, working with his Ph.D. advisor, ECE Associate Professor Siddharth Rajan, was beneficial.
“He has been guiding me through all these experiments and ideas,” he said. “He’s pretty open-minded, and he likes to discuss and exchange all sort of research ideas.”
Zhang is scheduled to receive his Ph.D. in summer 2018. He has plans for post-doc research outside of Ohio State.
Since ISSLED is a bi-annual conference, his plans for returning are still undecided, but Zhang recommends other students attend.
“It’s a very highly-professional conference; there are researchers from all over the world,” he said. “They are all the very top researchers, too, so I enjoyed it a lot.”
Story by ECE Student PR Writer, Lydia Freudenberg
