Silicon element “deformation”

  People tend to be more impressed by the first place. For example, the first element in the earth’s crust is oxygen. Is it second only to it? The answer is silicon, which accounts for about 27% of the total mass of the earth’s crust. Although rich in content, it is difficult to find its element in nature, usually in the form of silicates and silica, which we can find in rocks. Although silicon is less than oxygen, it has even more amazing applicability. With silicon, you have a powerful electronic device, and you have the Internet society.
  But the application of silicon seems to have stalled, so scientists have tried to “disguise” silicon and have achieved impressive results. Why is the application of silicon stagnant? What are these “disguised” silicon? Let’s take a look together.
  The speed of silicon chips is “to the end”
  In electronic devices, silicon chips can be said to be core devices. From smartphones, ultra-thin laptops to pacemakers, their chips are made of silicon. Almost every year, about 6.5 million square meters of chips are put into use, and some of them are put into computers and solar cells. However, as far as the current situation is concerned, the application efficiency of silicon on computers and solar cells seems to have reached the upper limit.
  At present, small computer silicon chips are already crowded because they are crowded with silicon transistors made of semiconductor silicon. As the basic equipment for computer processing information, one of the most important characteristics of silicon transistors is to act as a resistor to realize voltage-to-current switching control. The switch here refers to the presence and absence of current. Why would you choose semiconductor silicon as the main raw material?
  First, we need to understand why we choose semiconductors. Because if it is a transistor made of a conductor, because the conductivity of the conductor is too strong, when a small voltage is applied, a current is generated, so that the transistor is always “on”; if it is an insulator, no matter how much voltage is applied. It also does not generate current, and the transistor will remain in the “off” state. Such a transistor cannot achieve voltage-to-current switching control. But the semiconductor is different. Its conductivity is between the conductor and the insulator. When a small voltage is applied, it can’t generate current like the insulator. At this time, the transistor is in the “off” state; when the voltage is applied When larger, the semiconductor produces the same current as the conductor, and the “on” information can be transmitted at this time. In this way, the semiconductor can switch back and forth between two different states of the switch when different voltages are applied, so that the current can be controlled, so that the semiconductor becomes the main material of the transistor.
  Secondly, the reason for choosing silicon is actually very simple. Because silicon is rich in the earth’s crust, it is cheaper than bismuth and gallium arsenide, and can be used for mass production. Therefore, semiconductor silicon has become a transistor for decades. Preferred material.
  The greater the number of transistors on a chip, the more information can be processed at the same time, and the faster the processing of this computer. At the same time, however, the more heat generated by the transistor at the same time, the more heat will adversely affect the efficiency of the chip, so the number of transistors that can be loaded on a chip is limited. And silicon has also played almost 100% of its usability, which is why computer processing speed has been stagnant in the past decade.
  Low photoelectric conversion efficiency
  in solar cells, silicon prospects look increasingly dim, as it converts light energy into electrical energy efficiency is too low, this is why? Originally in solar silicon cells, there are two different kinds of silicon, one with surplus electrons on silicon; the other with electron holes on the silicon, which can be used to store electrons.
  Light is a stream of particles ejected from the sun. There are countless photons in a beam of light. They are small, small particles. When light strikes a silicon cell, some of the photons hit the surplus electrons of the silicon atoms and “knock” the electrons out of the silicon atoms. The “knocked” electrons are looking for a place to store it, at which point it moves into the electron cavity, and the movement of the electron produces a current. In silicon cells, many similar impacts occur, and a large number of electrons that are struck are constantly “going” to electron holes, and electrons are not just “settling” on an electron hole, but in multiple electrons. The hole moves continuously until a specific moving path is formed, at which time the electrons are oriented to generate a current, so that the light energy is converted into electrical energy.
  But the light is reflected. After the light hits the surface of the silicon cell, part of the light will be reflected, and this part of the light cannot be converted into electrical energy. At the same time, the electrons that are “knocked out” are moving, some of them may be “grabbed” into their orbit by other silicon atoms. These electrons cannot move continuously, nor do they enter a specific route. When it is reduced, the generated current intensity becomes weak, and the efficiency of converting light energy into electric energy becomes low.
  To this end, the researchers have considered other materials such as cadmium telluride and gallium arsenide, but the elements such as antimony and gallium are relatively expensive and are not expensive enough to meet the requirements of today’s Internet society. Some elements may even It is toxic and poses a threat to the environment. Scientists have also considered graphene, which is stronger and lighter than silicon, and its photoelectric conversion efficiency is much better than that of silicon batteries, but it is very difficult to produce graphene in large quantities. A common method for producing graphene is mechanical stripping, and single-layer graphene is very thin, so stripping requires a very high precision instrument. In general, the more precise the instrument, the more difficult it is to make and the higher the cost.
  It seems that hope can only be deposited on silicon.
  ”Deformation” The Three Musketeers silicon
  since silicon is still the computer chips and solar cells, “the main go-getters”, the scientists had to continue to study how to make the silicon becomes an appearance. Now, scientists have achieved impressive results.
  In the field of computer chips, a peculiar form of transistor was born in the hands of scientists – silene. Similar to graphene, silene has only a thin planar structure. Unlike graphene, it consists of silicon atoms, which are hexagonal in shape connected by six silicon atoms. The crystals are simply quite different.
  In a traditional silicon crystal, each silicon atom has four “touchers” that can connect four other silicon atoms. As the number of connected silicon atoms increases, silicon forms a cubic silicon crystal, and silylene It is flat. We know that the transistors mounted on the chip are made of silicon. The conventional silicon is a cubic silicon crystal. It is bulky and the transistor is made larger. Only a thin layer of silicon is used. The smaller the volume, the smaller the volume, the more transistors that the same size chip can hold, the more transistors can process more information at the same time, and the processing speed of the computer will also be faster.
  But the small size does not mean perfection. Since the silicon ene is only a plane, its structure is very unstable. Just as the quadrilateral is more deformable than the cube, the silylene is more easily decomposed, so the transistor made of silene may only be a few minutes. The “life”, so silene is currently not really applied in real life.
  In the field of solar cells, the allotrope of silicon seems to have been favored by scientists. The staff of a research institute has been working to achieve the “deformation” of silicon, and ultimately has amazing results. Developers say they have developed a new silicon material, the Na4Si24 crystal, which is a blue shiny crystal that is extruded from silicon and sodium.
  The researchers found that the Na4Si24 crystal is a “corridor” structure, just as people can walk around in the corridor, sodium ions can easily “walk around” in the silicon “corridor”. The researchers tried to heat the crystals and found that the sodium ions could easily slide out of the “corridor” under the heat, and when the sodium ions all slipped out of the “corridor,” the researchers got the allotropes of silicon. Si24. After comparison, it is more efficient to convert light energy into electrical energy than ordinary silicon crystal. Researchers believe that if Si24 can be mass-produced, it will produce more efficient solar cells.
  In addition to Si24, another silicon isoform, silicon BC8, can also be used to make solar cells. As mentioned above, in a conventional silicon battery, light is irradiated on the surface of a silicon cell, and a part of photons are absorbed by the silicon cell, and photons hit the electrons of the silicon atom, and the electrons are directionally moved to form a current. In this process, a photon generally “knocks” out an electron and then fails, and the photon utilization rate is very low. If there are fewer photons on a cloudy or rainy day, fewer electrons are struck, and less current is generated, so the efficiency of converting silicon energy into electrical energy becomes worse. .
  But silicon BC8 can be different. The special structure of silicon BC8 allows a single photon to enter and can strike multiple electrons, which can cause multiple electrons to move in a directional manner. The more electrons move, the more current intensity may be generated. In this way, even with only a small number of photons, silicon BC8 can make full use of photons, “knock out” a large amount of electrons in the silicon battery, and directional movement, the light energy will be converted into electric energy in a large amount, thereby improving the cloudy and rainy days. Conversion efficiency of solar silicon cells.
  The “deformation” of silicon actually turns one form of silicon into another form, like a similar form, which speeds up the processing speed of computer chips and improves the efficiency of solar cells. But unfortunately, they still can’t really shine in the real world. Even so, scientists will not shrink back, because “getting it right” is the charm of science.