Kroemer, Herbert (1928- )

German physicist who with Russian physicist Zhores I Alferov and US electrical engineer Jack S Kilby shared the Nobel Prize for Physics in 2000 for their contributions to the field of information and communication technology. Kroemer played a leading role in the development of semiconductor heterostructures used in high-speed electronics applications and optoelectronics (the branch of electronics concerned with the development of devices that respond to both electrons and photons).

In 1957, Kroemer was the first to propose a transistor made from a heterostructured semiconductor. Heterostructured semiconductors, such as gallium arsenide, are made up from alternating thin layers of semiconducting materials. Kroemer's heterotransistor was superior to a conventional device, especially in applications involving high frequency and current amplification. Amplifiers using heterostructured semiconductor components have lower electrical noise than those using conventional components. Heterotransistors are used in the manufacture of mobile phones and are essential for satellite communications. In 1963, Kroemer proposed the principle behind a heterostructure-based laser, independently of Alferov.

Kroemer was employed at RCA Laboratories, Princeton, New Jersey, between 1954 and 1957 and then worked at Varian Associates, Palo Alto, California, from 1959 to 1966. He was appointed professor of physics at the University of Colorado, Boulder, in 1968, becoming professor of physics at the University of California at Santa Barbara in 1976.