Herbert Kroemer
Encyclopedia
Herbert Kroemer a professor of electrical and computer engineering at the University of California, Santa Barbara
University of California, Santa Barbara
The University of California, Santa Barbara, commonly known as UCSB or UC Santa Barbara, is a public research university and one of the 10 general campuses of the University of California system. The main campus is located on a site in Goleta, California, from Santa Barbara and northwest of Los...

, received his Ph.D. in theoretical physics
Theoretical physics
Theoretical physics is a branch of physics which employs mathematical models and abstractions of physics to rationalize, explain and predict natural phenomena...

 in 1952 from the University of Göttingen, Germany, with a dissertation on hot electron effects in the then-new transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...

, setting the stage for a career in research on the physics of semiconductor device
Semiconductor device
Semiconductor devices are electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors. Semiconductor devices have replaced thermionic devices in most applications...

s. In 2000, Dr. Kroemer, along with Zhores I. Alferov, was awarded a Nobel Prize in Physics
Nobel Prize in Physics
The Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and...

 "for developing semiconductor heterostructures used in high-speed- and opto-electronics". The other co-recipient of the Nobel Prize was Jack Kilby
Jack Kilby
Jack St. Clair Kilby was an American physicist who took part in the invention of the integrated circuit while working at Texas Instruments in 1958. He was awarded the Nobel Prize in physics in 2000. He is credited with the invention of the integrated circuit or microchip...

 for his invention and development of integrated circuits and micro-chips.

He had an early success in a rather different subject, when together with Burgess and Houston in 1953, he detected a mathematical error in Nordheim's theory of electron tunneling through the image-force rounded barrier used in the theory of field electron emission. Between them, they generated tables of correction-factor values that are still in use over 50 years later.

He worked in a number of research laboratories in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and taught electrical engineering
Electrical engineering
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...

 at the University of Colorado
University of Colorado at Boulder
The University of Colorado Boulder is a public research university located in Boulder, Colorado...

 from 1968 to 1976. He joined the UCSB faculty in 1976, focusing its semiconductor research program on the emerging compound semiconductor technology rather than on mainstream silicon
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...

 technology.

Professor Kroemer was elected as a member of the National Academy of Engineering
National Academy of Engineering
The National Academy of Engineering is a government-created non-profit institution in the United States, that was founded in 1964 under the same congressional act that led to the founding of the National Academy of Sciences...

 in 1997 and the National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...

 in 2003. Professor Kroemer has always preferred to work on problems that are ahead of mainstream
Mainstream
Mainstream is, generally, the common current thought of the majority. However, the mainstream is far from cohesive; rather the concept is often considered a cultural construct....

 technology
Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes ;...

. In the 1950s, he invented the drift transistor
Drift-field transistor
The drift-field transistor, also called the drift transistor or graded base transistor, is a type of high-speed bipolar junction transistor having a doping-engineered electric field in the base to reduce the charge carrier base transit time....

 and was the first to point out that advantages could be gained in various semiconductor devices by incorporating heterojunction
Heterojunction
A heterojunction is the interface that occurs between two layers or regions of dissimilar crystalline semiconductors. These semiconducting materials have unequal band gaps as opposed to a homojunction...

s into the devices. Most notably, in 1963 he proposed the concept of the double-heterostructure laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

, which is now a central concept in the field of semiconductor lasers. Kroemer became an early pioneer in molecular beam epitaxy
Molecular beam epitaxy
Molecular beam epitaxy is one of several methods of depositing single crystals. It was invented in the late 1960s at Bell Telephone Laboratories by J. R. Arthur and Alfred Y. Cho.-Method:...

, concentrating on applying the technology to untried new materials.

Along with Charles Kittel
Charles Kittel
Charles Kittel is an American physicist. He was a Professor at University of California, Berkeley from 1951 and has been Professor Emeritus since 1978.- Life and work :...

 he co-authored the popular textbook Thermal Physics, first published in 1980, and still used today. He is also one of the celebrated authors of another textbook, Quantum Mechanics for Engineering, Materials Science and Applied Physics.

See also


External links

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