Russian scientists have discovered the "impossible" effect
Apr 01, 2019

Russian scientists have discovered the "impossible" effect

Russian scientists were able to find that one of the effects used in the creation of lasers and LEDs can work in "pure semiconductors", which was previously considered impossible, according to the journal Semiconductor Science and Technology.

"If in the case of silicon and germanium cryogenic temperatures are required, which calls into question the value of this effect, then in materials such as diamond and gallium nitride, it can be observed already at room temperature. This means that this effect can be used in the creation of devices for the mass market," said Dmitry Fedyanin, an employee of the Moscow Institute of physics and technology.His team has been working on new sources of light particles for several years. Scientists are studying exotic materials that are practically not used in the manufacture of LEDs and other emitters or are not used in principle, writes RIA "Novosti".Recently, Fedyanin and his colleague Igor Khramtsov discovered another effect that makes diamonds one of the most promising materials when creating cheap and compact or very powerful semiconductor lasers.It is reported that diamonds and other "pure" conductors could not get into the production of lasers and LEDs, since there are few electrons and "holes" inside them (that is, areas with a positive charge, whose interactions generate light particles). However, about 50 years ago, Soviet physicists together with the German were able to solve this problem: they proved that it is possible to use not one type of material, but something like a "sandwich" of different semiconductors with specially selected properties. Semiconductor interactions lead to the fact that the concentration of one of the types of charge carriers in the center of the "sandwich" or at the boundaries between its layers grows by several orders of magnitude.Later this phenomenon was called "superinjection". Currently, it is actively used in the creation of semiconductor lasers used for the Assembly of all modern electronic gadgets. Scientists believed that it can occur only in the interactions of semiconductors with different composition.Thus, scientists could not create powerful solid-state lasers based on "pure" silicon and other materials that are used in "printing" chips. However, experts from Russia proved the opposite by calculating the behavior of electrons and "holes" inside the "sandwich" of diamond plates, which are saturated with different types of impurities.Experiments have shown that in the presence of a fairly large number of layers in the design there is an effect that is similar to superinjection. This allows the concentration of electrons inside the "sandwich" to be about 10 thousand higher than was thought possible in the past. In addition, diamonds are superior to "conventional" multilayer lasers and LEDs by about 100 times.The press service of MIPT said that thanks to this discovery it will be possible to create thousands of times brighter than predicted in the calculations, ultraviolet LEDs. Collect them will not only from diamonds, but also from other superconductors with similar properties. This will reduce their cost and thus increase power. m

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