1833, the British scientist Faraday, the father of electronics, first discovered that the resistance of silver sulfide varies with temperature, which is different from that of ordinary metals. Generally speaking, the resistance of metal increases with the increase of temperature, but ElBaradei found that the resistance of silver sulfide material decreases with the increase of temperature. This is the first time that a semiconductor phenomenon has been discovered.
Soon, in 1839, Becker discovered that the junction formed by the contact of semiconductor and electrolyte would generate voltage under illumination, which was later called photovoltaic effect, which was the second characteristic of semiconductor discovered.
1873, Smith of Britain discovered the photoconductive effect of selenium crystal material with increased conductance under illumination, which is another unique property of semiconductor.
Although these four effects of semiconductors (the discovery of four associated effects and the remaining achievements of Jane Hall effect) were discovered one after another before 1880, the term semiconductor was first used by Kauniberg and Weiss about 19 1 1 years ago. Summing up these four characteristics of semiconductors, Bell Laboratories didn't finish it until June1947+February.
In 1874, Braun observed that the conductivity of some sulfides is related to the direction of the applied electric field, that is, their conductivity is directional, and it will conduct when a DC voltage is applied across them; If the voltage polarity is reversed, it will not conduct electricity, which is the rectification effect of semiconductors and the third characteristic of semiconductors. In the same year, Schuster discovered the rectification effect of copper and copper oxide.
Extended data:
Role contribution:
1, British scientist Faraday (michael faraday, 179 1~ 1867)
He has made many contributions to electromagnetism, but little known is one of the semiconductor materials he discovered in 1833.
Silver sulfide, because the resistance decreases with the increase of temperature, only felt a little strange at that time, and did not arouse much spark;
Today, however, we already know that with the increase of temperature, the lattice vibration becomes more intense, which makes the resistance increase. However, for semiconductors, the increase of temperature increases the concentration of free carriers, which is helpful to conduction, which is also a very important physical property of semiconductors.
2. Braun, Germany (1850~ 19 18).
It is noted that the conductivity of sulfide is related to the direction of applied voltage, which is the rectification of semiconductor.
However, it was not until 1906 that American motor inventor Picard (1877~ 1956) invented the first solid-state electronic component: cat whiskers, which used the rectification generated by the contact of metal with silicon or lead sulfide to detect radio waves.
In the aspect of rectification theory, Walter Schottky of Germany (1886 ~1976) published an important paper on rectification theory in 1939, and made many inferences. He believes that there is a potential barrier between metal and semiconductor, the main reason is.
3. Bloch (felix bloch, 1905~ 1983)
He has made an important contribution in this respect. His theorem is to add a periodic term to the electron wave function, which is the first in the energy band theory.
On the other hand, the German Pailes (1907~) pointed out an almost completely filled energy band in 1929, and its electrical characteristics can be explained by some positively charged charges, which is the origin of the concept of holes.
The perturbation theory he later proposed explained the existence of energy gap.
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