Origin of The Concept of Quantum Wells
In 1972, Charles H. Henry, a physicist and newly-appointed Head of the Semiconductor Electronics Research Department at Bell Laboratories, had a keen interest in the subject of integrated optics, the fabrication of optical circuits in which the light travels in waveguides.
In late 1972, while pondering the problems associated with waveguides, he had a sudden insight, a realization that a double heterostructure is a waveguide for electron waves, not just lightwaves. On further reflection, he saw that there is a complete analogy between the confinement of light by a slab waveguide and the confinement of electrons by the potential well that is formed from the difference in bandgaps in a double heterostructure.
Henry realized that there should be discrete modes (levels) in the potential well, and a simple estimate showed that if the active layer of the heterostructure is as thin as several tens of nanometres, the electron levels would be split apart by tens of milli-electron volts, which should be observable. This structure is now called a quantum well.
Henry then calculated how this quantization would alter the optical absorption edge of the semiconductor. His conclusion was that instead of the optical absorption increasing smoothly, the absorption edge of a thin heterostructure would appear as a series of steps.
In addition to Henry's contributions, the quantum well (or double-heterostructure laser, as it was originally known) was actually first proposed in 1963 by Herber Kroemer in Proceedings of the IEEE and simultaneously (in 1963) in the U.S.S.R by Zh. I. Alferov and R.F. Kazarinov. Alferov and Kroemer shared a Nobel Prize in 2000 for their work in semiconductor heterostructures.
Read more about this topic: Quantum Well Laser
Famous quotes containing the words origin of, origin, concept, quantum and/or wells:
“There are certain books in the world which every searcher for truth must know: the Bible, the Critique of Pure Reason, the Origin of Species, and Karl Marx’s Capital.”
—W.E.B. (William Edward Burghardt)
“The essence of morality is a questioning about morality; and the decisive move of human life is to use ceaselessly all light to look for the origin of the opposition between good and evil.”
—Georges Bataille (1897–1962)
“The concept of a person is logically prior to that of an individual consciousness. The concept of a person is not to be analysed as that of an animated body or an embodied anima.”
—Sir Peter Frederick Strawson (b. 1919)
“The receipt to make a speaker, and an applauded one too, is short and easy.—Take of common sense quantum sufficit, add a little application to the rules and orders of the House, throw obvious thoughts in a new light, and make up the whole with a large quantity of purity, correctness, and elegancy of style.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)
“All through the nineties I met people. Crowds of people. Met and met and met, until it seemed that people were born and hastily grew up, just to be met.”
—Carolyn Wells (1862–1942)