By Sara Cody
Colleagues from around the world came to campus on Dec. 2 to honor the career of Professor Emeritus Theodore Moustakas (ECE, MSE) at a symposium focused on his signature innovation, a process that makes the glowing screens on today’s ubiquitous electronic devices possible, as well as other discoveries.
The symposium, “III-Nitride Semiconductor Materials and Devices Symposium,” was fittingly held in the Photonics Center, a building Moustakas had a leading hand in creating.
“The ubiquity of Ted’s work in blue LEDs, used in laptops, cell phones and a myriad of other lighting and backlit devices, makes his work seminal to basically everyone in society today,” said Boston University President Robert A. Brown in his opening remarks. “However, to me, one of Ted’s most important contributions is as an early pioneering research leader at Boston University.”
Moustakas invented and patented a process currently being used to create blue light-emitting diodes (LEDs), utilized in many devices today. When LEDs were invented more than 40 years ago, they were made with a compound called gallium arsenide, which emitted a faint red and green glow, and was used in products like digital clocks and calculator displays. It was hypothesized that a compound called gallium nitride, which emits a blue light, would produce a brighter light, but the structure of the semiconductor crystals at the time did not support the much-smaller blue wavelengths.
Moustakas solved this problem by creating the buffer-layer process, a two-step method that bridges the gap between the semiconductor crystals and the blue wavelengths, publishing his findings in 1991. To this day, it is the only known way to make blue LEDs, and is still used in the technology that people interact with on a daily basis, such as smartphones, televisions and lightbulbs.
Last year, BU and Moustakas won a $13 million judgment in federal court against three major companies which were determined to have willfully infringed on the patented technology he developed. The three Taiwan-based companies manufacture or package LEDs for consumer electronics for big-name electronics companies. Though these major companies were named on the initial case, they settled out of court while agreeing to licensing and confidentiality agreements.
While Moustakas was publishing his findings with gallium nitride, Shuji Nakamura, an engineer from Japan who is now a Professor at the University of California at Santa Barbara, was working on similar technology. Though initially Nakamura and Moustakas were competitors racing to patent their technologies, they remain cordial colleagues, and Nakamura gave a keynote speech about the blue LED technology at the symposium.
In addition to Nakamura, the symposium hosted a variety of speakers, experts in the field of semiconductors, who came to speak about their own work and research and honor Moustakas’ career. Other speakers included:
- Charles Eddy, US Naval Research Laboratory: “Advancing III-N Semiconductors in New Directions.”
- Professor Asif Khan, University of South Carolina: “High Al-content AlxGa1-xN Heterojunctions for Devices in the Deep Ultraviolet Part of the Spectrum.”
- Professor Philomela Komninou, Aristotle University of Thessaloniki, Greece: “Nanostructures and Interfaces in Epitaxial III-Nitride Semiconductors.”
- Eva Monroy, CEA Grenoble: “Plasma-assisted MBE of III-Nitride Semiconductors and its Applications to Intersubband Devices.”
- Professor Fernando Ponce, Arizona State University: “Microstructure and Polarization Properties of III-N Semiconductors.”
- Professor David Smith, Arizona State University: “Exploring III-Nitrides with Advanced Electron Microscopy Techniques.”
- Professor Tadeusz Suski, Polish Academy of Sciences, Warsaw: “From High-Pressure Bulk GaN Crystals to InGaN/GaN Quantum Structures and Light Emitters.”
Along with Moustakas’ contributions to the field of LEDs, he was also a key player in the quest to build the Photonics Center, which was established in 1993. Today, the Photonics department is a robust collaborative of faculty and graduate students who create new light-based materials, devices and systems, and use them to impact society. When Professor Thomas Bifano (ME), director of the Photonics Center, spoke about the history of the building, he credited Moustakas’ leadership in writing a complex grant proposal that led to funding by the Department of Defense.
“Ted, along with his colleagues, wrote a beautifully rich document with very high technical detail filled with great ideas about how the Boston University Photonics Center could transform both defense and society,” said Bifano. “Today, the three core values of the Photonics Center are we lead interdisciplinary research, we share community resources and we promote technology translation. There is no doubt that the lead person in establishing this was Ted Moustakas.”
When Moustakas stood to provide closing remarks for the symposium, he recounted his life experience that led him to BU. Born in a small village in Greece during the World War II, at a time of political upheaval and civil war in his country, his hometown did not have electricity until he was a teenager. He recounted a formative experience he had growing up that forever altered his outlook on life, when his high school teacher gave him a book written by Greek author Nikos Kazantzakis that included the famous quote “reach what you cannot.”
“This quote is what has driven me throughout my life, and I try to instill the same spirit on my children and graduate students. Keep going as far as you cannot go, and you will make discoveries along the way,” said Moustakas. “I grew up reading by candlelight or a petroleum lamp, so I feel very humble looking back at my career and hearing your kind words about how I contributed to this technology that produces light.”