Philips Electronics Honors Professor Gertrude Neumark
Prof. Neumark is the reason a new professorship is being established at the School. Philips, the international electronics company headquartered in The Netherlands, established an endowed fund, the newly-created Philips Electronics Professorship Fund, in the School’s Department of Applied Physics and Applied Mathematics in honor of Professor Neumark’s pioneering role as a woman scientist and engineer. She was employed by Philips Laboratories in Briarcliff Manor, NY, between 1960 and 1985.
The Philips Electronics Professorship is to be held by a tenured faculty member and consideration will be given to a member who is from a group that is underrepresented on the SEAS faculty with a view toward increasing the diversity of the School, as Prof. Neumark did at the time of her appointment as Howe Professor of Materials Science in 1999. Dean Navratil said, “We know the incumbent will be inspired by the example of Gertrude Neumark.”
Prof. Neumark said, “I am particularly pleased that the Philips Electronics Professorship will give one member of an underrepresented group an opportunity to receive tenure.” Prof. Neumark is one of the world’s foremost experts on doping wide band-gap semiconductors. It was during her research work at SEAS that she conceived the doping process that has been the basis for devices improving the quality of consumer products ranging from flat screen TVs to mobile phone screens.
“Columbia revitalized my research and really gave me a second career,” says Neumark, currently a research scientist and Howe Professor emerita. “I find the environment extremely stimulating.” She credits Columbia with providing the creative environment that led to her patents in doping wide band-gap semiconductors.
Doping is the process of adding impurities to semiconductors to provide better conductivity. There are two types of dopants, one with one more valence electron than the host (donors), and the other with one fewer (acceptors). Prof. Neumark realized that better doping could be obtained by “tricking” the semiconductor by incorporating both types of dopants together, but selecting the type that was not desired to be a relatively mobile impurity, and then subsequently removing it.
Moreover, she also realized that this method would be applicable to any wide band-gap material. It was precisely this approach that resulted in the successful development of green and shorter-wavelength lasers and LEDs using gallium nitride and related nitrides. For a number of years, obtaining efficient blue and green light emissions from semiconductor devices was regarded as the “holy grail” in this area.
Commercial uses for blue and shorter-wavelength lasers range from increasing sharpness of a laser printer to increasing the information storage capacity of a DVD. The significant advantage of these diode lasers lies in their wavelength. “The space needed to store information is proportional to the square of the wavelength,” said Neumark, “so the shorter the wavelength, the greater the information that can be stored in the same space.”
In addition to these lasers, her patented processes led to blue and ultraviolet LEDs (light-emitting diodes), which are now used for computers, traffic lights, instrument panels, as the background color for mobile-phone screens, in multicolor displays, flat screens and in numerous other lighting applications.