Bright light, big idea
Nick Holonyak Jr.: Father of the visible LED
By Laura Schmitt
On the afternoon of November 6, 2003, Nick Holonyak Jr., the son of an uneducated immigrant coal miner, stood in the East Room of the White House waiting to receive the National Medal of Technology from President George W. Bush. Perhaps he felt a sense of déjà vu. After all, 13 years earlier, Holonyak received the National Medal of Science from Bush’s father in a White House ceremony. Only five other people have received both medals, which are the highest honors the president can bestow for attainment in science and technology.
This second trip to the White House was special to Holonyak for another reason. He was receiving the Technology Medal with M. George Craford and Russell Dupuis, both former students who had earned their doctorates under his supervision at Illinois. The three were honored for their contributions to developing and commercializing LED technology with applications to digital displays, consumer electronics, automotive lighting, traffic signals, and general illumination. Holonyak invented the world’s first visible and practical semiconductor LED and laser in 1962 while at General Electric; Craford invented the world’s first yellow LED and led subsequent R&D efforts that resulted in the highest-brightness LEDs; Dupuis developed a new crystal growth method—metal-organic chemical vapor deposition (MOCVD)—for making lasers and LEDs. Today, MOCVD dominates LED production.
“The semiconductor in the form of a p-n junction is an ultimate lamp,” said Holonyak, referring to the engineered part of a semiconductor chip that emits light. “There’s nothing more efficient.” Interestingly, Holonyak knew that from the start, predicting in a 1963 Reader’s Digest article that LEDs would someday replace Edison’s incandescent bulb, which converts only 10 percent of its electricity into light, losing the other 90 percent as heat. An LED, on the other hand, can convert nearly all the electricity applied to it into light.
Because lighting accounts for about 20 percent of all electricity generated globally, the LED’s efficiency will result in a marked decline in energy consumption. According to a recent government study, the adoption of LED lighting over 20 years in the United States alone (2010–2030) is expected to save 2,700 terawatt-hours of electricity, which translates into roughly $250 billion at today’s energy prices. That’s good news for consumers who today pay almost 30 percent more for electricity than they did just 10 years ago.
The savings will occur primarily as LEDs become the dominant form of lighting, replacing the inefficient incandescent bulb and its ill-fated successor, the compact fluorescent light (CFL), whose light quality, dimming capability, and longevity are inferior to LEDs. Holonyak’s 1962 invention was the byproduct of a competition among leading industrial research labs to create the first semiconductor laser. Unlike his competitors, who made their lasers, which could only generate infrared light, from conventional semiconductor material readily available at the time, Holonyak made his red laser from an unorthodox mixture of semiconductor materials of his own invention. He was certain that his alloy, made from gallium, arsenic, and phosphorus (GaAsP), would produce efficient and bright light, including laser light.
At the time, Holonyak endured criticism from his colleagues, who told him that an alloy could never make a reliable device. “They said I was nuts—an alloy is too hard to work with and its chemistry was all screwed up,” said Holonyak. “They said I was just a stupid electrical engineer and no one in his right mind would have tried to make a crystal that way. They swore at me and in return I swore at them.”
Although dim by today’s standards, Holonyak’s first red LED proved that an alloy could be used to make light-emitting devices. “I’m not a chemist or a metallurgist, but I made the alloy crystals myself because I couldn’t get them—they didn’t exist—and I needed and wanted them, and I had a way to do it,” Holonyak said. “I followed my own notions on how to grow GaAsP and make red-spectrum p-n junctions.”
According to Michael Krames, chief technology officer at LED startup Soraa, Holonyak created a roadmap that others would follow in achieving brighter and different color LEDs over the years. Today, all visible LEDs are made from a family of semiconductor alloys that Holonyak pioneered. In addition, Holonyak introduced a new laser design—the quantum well laser—in 1977 that would be used to make brighter and more efficient LEDs. “It’s hard to really appreciate how momentous and impactful some of these breakthroughs were,” said Krames, who earned his doctorate at Illinois under Holonyak’s supervision in 1995. “They were huge. Back in his day, all of this stuff was completely unknown. It wasn’t clear what to do until he and others showed the way.”
Holonyak is the first to acknowledge that many researchers have played a role in advancing LED technology. “I feel privileged to have contributed a piece at the start of all of this, to an ultimate lamp, and to have had a core of talented students following me and leading the field in making high-brightness LEDs,” Holonyak said. “It takes a lot of effort from a lot of people over a considerable time and nobody sitting in one place has all the answers. Science and technology comes about slowly, painfully.”
Editor’s note: This article is excerpted from Laura Schmitt’s forthcoming book, The Bright Stuff.