Herbert Kroemer
University of California, Santa Barbara
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Primary Section: 33, Applied Physical Sciences Secondary Section: 31, Engineering Sciences Membership Type:
Emeritus
(elected 2003)
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Research Interests
Most of my research interests concern the Physics and Technology of Semiconductors and Semiconductor Devices. Within this broad field, there have been four overlapping areas of emphasis: (a) Semiconductor heterostructures have been a dominant theme from the beginning of my research career, starting with an inquiry into the effects of energy gap variations on the carrier transport in structures containing a position-dependent gap. This led to device concepts such as heterostructure bipolar transistors and double-heterostructure lasers. Work on the physics of the band lineups at abrupt hetero-interfaces followed, which in turn led to continuing research on quantum well and superlattice structures. (b) A second area, also dating from the beginning of my research career, has been nonlinear electron transport, especially negative-resistance effects at high electric fields, ranging from the Gunn effect in bulk semiconductors to Bloch oscillations in superlattices. (c) Molecular-beam epitaxy technology of semiconductor systems other than the GaAs/AlGaAs system -- and of heterostructures based on them -- was an important area of my research from 1977 through 1999. (d) Straddling the border between semiconductors and supercondutors is research on semiconductor-coupled superconductive weak links in the almost unexplored near-ballistic "clean" limit.
