At the College of New Jersey in Ewing, the Sarnoff Collection says of itself that it’s “named in honor of David Sarnoff, longtime chairman of the Radio Corporation of America (RCA) and internationally renowned pioneer in radio and television” and that it holds “over 6000 artifacts that document major developments in communication and electronics in the 20th century.” In a 10 October Wall Street Journal op-ed, Sarnoff curator Benjamin Gross asserts RCA’s importance in the prehistory of the 2014 Nobel Prize in Physics. At the American Institute of Physics, the report “Three scientists share physics Nobel prize for blue LEDs” by Inside Science News Service director Ben P. Stein opens with this summary of the recent award:
The 2014 Nobel Prize in physics has been awarded to two Japanese citizens and one U.S. citizen, all born in Japan, “for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources.” The prize goes jointly to Isamu Akasaki of Meijo University in Nagoya, Japan, Hiroshi Amano of Nagoya University in Japan, and Shuji Nakamura of the University of California, Santa Barbara. Starting in the 1990s they produced blue LEDs, an energy-efficient, environmentally friendly source of blue light, which could be mixed with LEDs of other colors to produce what the eye sees as white light.
Stein goes on to tell that scientific story reaching back 20 years and more. “For decades,” he writes at one point, “researchers had identified gallium nitride as a material that could potentially produce blue light very efficiently, but huge technological problems, which seemed insurmountable at times, stood in the way of a practical consumer device.” Gross wants the world to know more about those earlier decades, and about RCA’s contributions during them to solve those problems. “While the Nobel Committee says that the ‘invention of the blue LED is just twenty years old,’’’ Gross writes, “its history in fact dates from the late 1960s. And the story of the blue LED begins not in Japan but in New Jersey, at the Princeton laboratories of the Radio Corporation of America. As America’s leading consumer electronics firm, RCA was home to one of the nation’s largest semiconductor research groups.” He continues:
Germanium and silicon, the elements used in the first transistors and integrated circuits, received most of the RCA group’s attention. But the company was also interested in so-called compound semiconductors consisting of more than one element, such as gallium arsenide, which RCA’s Rubin Braunstein used to build the first infrared LED. ... Other LEDs, capable of generating red and green light, followed soon after. In spring 1968, James Tietjen—a chemist in RCA’s Material Research Laboratory—initiated a program aimed at creating a blue LED that, when combined with existing red and green LEDs, might enable the construction of a flat-panel color television. Rather than using gallium arsenide, Mr. Tietjen directed another scientist in his group, Herbert Maruska, to look at gallium nitride, a different compound semiconductor. In theory, gallium nitride would be able to produce a nice blue light, but growing the thin films of material required to construct an LED proved challenging.
Gross traces the difficult work that then led to “an LED capable of emitting blue-violet light,” noting that today, the Sarnoff Collection displays “this first-ever prototype blue LED.” He reports that the success “came at a terrible time for RCA,” then “slashing budgets in the wake of their recent withdrawal from the computer market.” Funding lapsed for compound-semiconductor research. The gallium nitride group disbanded, but “the RCA project continued to shape LED investigations around the world.” Gross mentions how that shaping affected the work of Akasaki, Amano, and Nakamura:
In 1972 the future Nobel laureate Isamu Akasaki learned about RCA’s gallium-nitride research from Jacques Pankove and later visited Princeton to learn more about its LED efforts. Mr. Akasaki and his graduate student Hiroshi Amano picked up where RCA left off, eventually creating a PN junction LED using gallium nitride in 1989. Shuji Nakamura, in turn, built upon that work to develop improved manufacturing techniques that enabled Nichia Chemicals to announce the mass production of blue LEDs in 1993.
At the end, Gross summarizes his argument:
The Japanese scientists who received this year’s Nobel Prize in Physics certainly deserve recognition. Together they made the blue LED a practical commercial product. But their work built on material research conducted decades earlier on the other side of the Pacific. Mr. Maruska’s prototype may not have matched the performance of its Japanese descendants, but it laid the foundation for the emergence of the LED—a truly international story that has been under way for over 40 years.
--- Steven T. Corneliussen, a media analyst for the American Institute of Physics, monitors three national newspapers, the weeklies Nature and Science, and occasionally other publications. He has published op-eds in the Washington Post and other newspapers, has written for NASA's history program, and is a science writer at a particle-accelerator laboratory.
