Physics Nobel Laureate Herbert Kroemer Dies at 95

IEEE also reflects on the lives of other members

8 min read
an elderly man with glasses and a beard posing for a portrait in a suit jacket and tie

IEEE Life Fellow Herbert Kroemer received the 2000 Nobel Prize in Physics for developing semiconductor heterostructures for high-speed and opto-electronics.

Henrik Montgomery/AFP/Getty Images

Herbert Kroemer

Nobel Laureate

Life Fellow, 95; died 8 March

Kroemer, a pioneering physicist, is a Nobel laureate, receiving the 2000 Nobel Prize in Physics for developing semiconductor heterostructures for high-speed and opto-electronics. The devices laid the foundation for the modern era of microchips, computers, and information technology. Heterostructures describe the interfaces between two semiconductors that serve as the building blocks between more elaborate nanostructures.

He also received the 2002 IEEE Medal of Honor for “contributions to high-frequency transistors and hot-electron devices, especially heterostructure devices from heterostructure bipolar transistors to lasers, and their molecular beam epitaxy technology.”

Kroemer was professor emeritus of electrical and computer engineering at the University of California, Santa Barbara, when he died.

He began his career in 1952 at the telecommunications research laboratory of the German Postal Service, in Darmstadt. The postal service also ran the telephone system and had a small semiconductor research group, which included Kroemer and about nine other scientists, according to IEEE Spectrum.

In the mid-1950s, he took a research position at RCA Laboratories, in Princeton, N.J. There, Kroemer originated the concept of the heterostructure bipolar transistor (HBT), a device that contains differing semiconductor materials for the emitter and base regions, creating a heterojunction. HBTs can handle high-frequency signals (up to several thousand gigahertz) and are commonly used in radio frequency systems, including RF power amplifiers in cell phones.

In 1957, he returned to Germany to research potential uses of gallium arsenide at Phillips Research Laboratory, in Hamburg. Two years later, Kroemer moved back to the United States to join Varian Associates, an electronics company in Palo Alto, Calif., where he invented the double heterostructure laser. It was the first laser to operate continuously at room temperature. The innovation paved the way for semiconductor lasers used in CD players, fiber optics, and other applications.

In 1964, Kroemer became the first researcher to publish an explanation of the Gunn Effect, a high-frequency oscillation of electrical current flowing through certain semiconducting solids. The effect, first observed by J.B. Gunn in the early 1960s, produces short radio waves called microwaves.

Kroemer taught electrical engineering at the University of Colorado, Boulder, from 1968 to 1976 before joining UCSB, where he led the university’s semiconductor research program. With his colleague Charles Kittel, Kroemer co-authored the 1980 textbook Thermal Physics. He also wrote Quantum Mechanics for Engineering, Materials Science, and Applied Physics, published in 1994.

He was a Fellow of the American Physics Society and a foreign associate of the U.S. National Academy of Engineering.

Born and educated in Germany, Kroemer received a bachelor’s degree from the University of Jena, and master’s and doctoral degrees from the University of Göttingen, all in physics.

Vladimir G. “Walt” Gelnovatch

Past president of the IEEE Microwave Theory and Technology Society

Life Fellow, 86; died 1 March

Gelnovatch served as 1989 president of the IEEE Microwave Theory and Technology Society (formerly the IEEE Microwave Theory and Techniques Society). He was an electrical engineer for nearly 40 years at the Signal Corps Laboratories, in Fort Monmouth, N.J.

Gelnovatch served in the U.S. Army from 1956 to 1959. While stationed in Germany, he helped develop a long-line microwave radiotelephone network, a military telecommunications network that spanned most of Western Europe.

As an undergraduate student atMonmouth University, in West Long Branch, N.J., he founded the school’s first student chapter of the Institute of Radio Engineers, an IEEE predecessor society. After graduating with a bachelor’s degree in electronics engineering, Gelnovatch earned a master’s degree in electrical engineering in 1967 from New York University, in New York City.

Following a brief stint as a professor of electrical engineering at the University of Virginia, in Charlottesville, Gelnovatch joined the Signal Corps Engineering Laboratory (SCEL) as a research engineer. His initial work focused on developing CAD programs to help researchers design microwave circuits and communications networks. He then shifted his focus to developing mission electronics. Over the next four years, he studied vacuum technology, germanium, silicon, and semiconductors.

He also spearheaded the U.S. Army’s research on monolithic microwave-integrated circuits. The integrated circuit devices operate at microwave frequencies and typically perform functions such as power amplification, low-noise amplification, and high-frequency switching.

Gelnovatch retired in 1997 as director of the U.S. Army Electron Devices and Technology Laboratory, the successor to SCEL.

During his career, Gelnovatch published 50 research papers and was granted eight U.S. patents. He also served as associate editor and contributor to the Microwave Journal for more than 20 years.

Gelnovatch received the 1997 IEEE MTT-S Distinguished Service Award. The U.S. Army also honored him in 1990 with its highest civilian award—the Exceptional Service Award.

Adolf Goetzberger

Solar energy pioneer

Life Fellow, 94; died 24 February

Goetzberger founded the Fraunhofer Institute for Solar Energy Systems (ISE), a solar energy R&D company in Freiburg, Germany. He is known for pioneering the concept of agrivoltaics—the dual use of land for solar energy production and agriculture.

After earning a Ph.D. in physics in 1955 from the University of Munich, Goetzberger moved to the United States. He joined Shockley Semiconductor Laboratory in Palo Alto, Calif., in 1956 as a researcher. The semiconductor manufacturer was founded by Nobel laureate William Shockley. Goetzberger later left Shockley to join Bell Labs, in Murray Hill, N.J.

He moved back to Germany in 1968 and was appointed director of the Fraunhofer Institute for Applied Solid-State Physics, in Breisgau. There, he founded a solar energy working group and pushed for an independent institute dedicated to the field, which became ISE in 1981.

In 1983, Goetzberger became the first German national to receive the J.J. Ebers Award from the IEEE Electron Devices Society. It honored him for developing a silicon field-effect transistor. Goetzberger also received the 1997 IEEE William R. Cherry Award, the 1989 Medal of the Merit of the State of Baden-Württemberg, and the 1992 Order of Merit First Class of the Federal Republic of Germany.

Michael Barnoski

Fiber optics pioneer

Life senior member, 83; died 23 February

Barnoski founded two optics companies and codeveloped the optical time domain reflectometer, a device that detects breaks in fiber optic cables.

After receiving a bachelor’s degree in electrical engineering from the University of Dayton, in Ohio, Barnoski joined Honeywell in Boston. After 10 years at the company, he left to work at Hughes Research Laboratories, in Malibu, Calif. For a decade, he led all fiber optics–related activities for Hughes Aircraft and managed a global team of scientists, engineers, and technicians.

In 1976, Barnoski collaborated with Corning Glass Works, a materials science company in New York, to develop the optical time domain reflectometer.

Three years later, Theodore Mainman, inventor of the laser, recruited Barnoski to join TRW, an electronics company in Euclid, Ohio. In 1980, Barnoski founded PlessCor Optronics laboratory, an integrated electrical-optical interface supplier, in Chatsworth, Calif. He served as president and CEO until 1990, when he left and began consulting.

In 2002, Barnoski founded Nanoprecision Products Inc., a company that specialized in ultraprecision 3D stamping, in El Segundo, Calif.

In addition to his work in the private sector, Barnoski taught summer courses at the University of California, Santa Barbara, for 20 years. He also wrote and edited three books on the fundamentals of optical fiber communications. He retired in 2018.

For his contributions to fiber optics, he received the 1988 John Tyndall Award, jointly presented by the IEEE Photonics Society and the Optical Society of America.

Barnoski also earned a master’s degree in microwave electronics and a Ph.D. in electrical engineering and applied physics, both from Cornell.

Kanaiyalal R. Shah

Founder of Shah and Associates

Senior member, 84; died 6 December

Shah was founder and president of Shah and Associates (S&A), an electrical systems consulting firm, in Gaithersburg, Md.

Shah received a bachelor’s degree in electrical engineering in 1961 from the Baroda College (now the Maharaja Sayajirao University of Baroda), in India. After earning a master’s degree in electrical machines in 1963 from Gujarat University, in India, Shah emigrated to the United States. Two years later, he received a master’s degree in electrical engineering from the University of Missouri in Rolla.

In 1967, he moved to Virginia and joined the Virginia Military Institute’s electrical engineering faculty, in Lexington. He left to move to Missouri, earning a Ph.D. in EE from the University of Missouri in Columbia, in 1969. He then moved back to Virginia and taught electrical engineering for two years at Virginia Tech.

From 1971 to 1973, Shah worked as a research engineer at Hughes Research Laboratories, in Malibu, Calif. He left to manage R&D at engineering services company Gilbert/Commonwealth International, in Jackson, Mich.

Around this time, Shah founded S&A, where he designed safe and efficient electrical systems. He developed novel approaches to ensuring safety in electrical power transmission and distribution, including patenting a UV lighting power system. He also served as an expert witness in electrical safety injury lawsuits.

He later returned to academia, lecturing at George Washington University and Ohio State University. Shah also wrote a series of short courses on power engineering. In 2005, he funded the construction and running of the Dr. K.R. Shah Higher Secondary School and the Smt. D.K. Shah Primary School in his hometown of Bhaner, Gujarat, in India.

John Brooks Slaughter

First African American director of the National Science Foundation

Life Fellow, 89; died 6 December

Slaughter, former director of the NSF in the early 1980s, was a passionate advocate for providing opportunities for underrepresented minorities and women in the science, technology, engineering, and mathematics fields.

Later in his career, he was a distinguished professor of engineering and education at the University of Southern California Viterbi School of Engineering, in Los Angeles. He helped found the school’s Center for Engineering Diversity, which was renamed the John Brooks Slaughter Center for Engineering Diversity in 2023, as a tribute to his efforts.

After earning a bachelor’s degree in engineering in 1956 from Kansas State University, in Manhattan, Slaughter developed military aircraft at General Dynamics’ Convair division in San Diego. From there, he moved on to the information systems technology department in the U.S. Navy Electronics Laboratory, also located in the city. He earned a master’s degree in engineering in 1961 from the University of California, Los Angeles.

Slaughter earned his Ph.D. from the University of California, San Diego, in 1971 and was promoted to director of the Navy Electronics Laboratory on the same day he defended his dissertation, according to The Institute.

In 1975, he left the organization to become director of the Applied Physics Laboratory at the University of Washington, in Seattle. Two years later, Slaughter was appointed assistant director in charge of the NSF’s Astronomical, Atmospheric, Earth and Ocean Sciences Division (now called the Division of Atmospheric and Geospace Sciences), in Washington, D.C.

In 1979, he accepted the position of academic vice president and provost of Washington State University, in Pullman. The following year, he was appointed director of the NSF by U.S. President Jimmy Carter’s administration. Under Slaughter’s leadership, the organization bolstered funding for science programs at historically Black colleges and universities, including Howard University, in Washington, D.C. While Harvard, Stanford, and CalTech traditionally received preference from the NSF for funding new facilities and equipment, Slaughter encouraged less prestigious universities to apply and compete for those grants.

He resigned just two years after accepting the post because he could not publicly support President Ronald Reagan’s initiatives to eradicate funding for science education, he told The Institute in a 2023 interview.

In 1981, Slaughter was appointed chancellor of the University of Maryland, in College Park. He left in 1988 to become president of Occidental College, in Los Angeles, where he helped transform the school into one of the country’s most diverse liberal arts colleges.

In 2000, Slaughter became CEO and president of the National Action Council for Minorities in Engineering, the largest provider of college scholarships for underrepresented minorities pursuing degrees at engineering schools, in Alexandria, Va.

Slaughter left the council in 2010 and joined USC. He taught courses on leadership, diversity, and technological literacy at Rossier Graduate School of Education until retiring in 2022.

Slaughter received the 2002 IEEE Founders Medal for “leadership and administration significantly advancing inclusion and racial diversity in the engineering profession across government, academic, and nonprofit organizations.”

Don Bramlett

Former IEEE Region 4 Director

Life senior member, 73; died 2 December

Bramlett served as 2009–2010 director of IEEE Region 4. He was an active volunteer with the IEEE Southeastern Michigan Section.

He worked as a senior project manager for 35 years at DTE Energy, an energy services company, in Detroit.

Bramlett was also active in the Boy Scouts of America (which will be known as Scouting America beginning in 2025). He served as leader of his local troop and was a council member. The Boy Scouts honored him with a Silver Beaver award recognizing his “exceptional character and distinguished service.”

Bramlett earned a bachelor’s degree in electrical engineering from the University of Detroit Mercy.

The Conversation (0)