Wiktionary
n. (context physics English) A semiconductor diode that has negative resistance in the forward direction of its operating range due to quantum effects.
Wikipedia
A tunnel diode or Esaki diode is a type of semiconductor that is capable of very fast operation, well into the microwave frequency region, made possible by the use of the quantum mechanical effect called tunneling.
It was invented in August 1957 by Leo Esaki when he was with Tokyo Tsushin Kogyo, now known as Sony. In 1973 he received the Nobel Prize in Physics, jointly with Brian Josephson, for discovering the electron tunneling effect used in these diodes. Robert Noyce independently came up with the idea of a tunnel diode while working for William Shockley, but was discouraged from pursuing it.
These diodes have a heavily doped p–n junction that is about 10 nm (100 Å) wide. The heavy doping results in a broken band gap, where conduction band electron states on the n-side are more or less aligned with valence band hole states on the p-side.
Tunnel diodes were first manufactured by Sony in 1957 followed by General Electric and other companies from about 1960, and are still made in low volume today. Tunnel diodes are usually made from germanium, but can also be made from gallium arsenide and silicon materials. They are used in frequency converters and detectors. They have negative differential resistance in part of their operating range, and therefore are also used as oscillators, amplifiers, and in switching circuits using hysteresis.
In 1977, the Intelsat V satellite receiver used a microstrip tunnel diode amplifier (TDA) front-end in the 14 to 15.5 GHz frequency band. Such amplifiers were considered state-of-the-art, with better performance at high frequencies than any transistor-based front end.
The highest frequency room-temperature solid-state oscillators are based on the resonant-tunneling diode (RTD).
There is another type of tunnel diode called a metal–insulator–metal (MIM) diode, but its present application appears to be limited to research environments due to inherent sensitivities. There is also a metal–insulator–insulator–metal MIIM diode which has an additional insulator layer. The additional layer allows "step tunneling" for precise diode control.
Usage examples of "tunnel diode".
When the scientists began to kick the quantum theory around they came up with any number of odd effects - the tunnel diode, the Josephson effect, and a lot more - some of them are usable and some not.
If you lived in a technology like that of the mid-twentieth century, you were there to see the vacuum tube displaced by the transistor and that by the tunnel diode, while in one ten-year period the artificial satellite moved from the area of laughable fantasy to a hunk of hardware broadcasting signals from the other side of the sun.
In the tunnel diode, simple probability is loaded with a voltage bias so that a current flows across the forbidden gap.
Until the timesubjectively, only an instant after her deathwhen she would come to awareness again, to find herself floating down a long tunnel diode, toward a bright light .
It ascertains whether new developments in technology, such as the transistor and the tunnel diode, have cryptographic applications.