Distinction of solar monocrystalline and polycrystalline silicon

The difference between the monocrystalline and polycrystalline silicon, when the solidification of the molten elemental silicon, silicon atoms are arranged in diamond lattice in many nuclei, if the crystal plane orientation of these nuclei grow into the same grain, the formation of monocrystalline silicon. If these nuclei grow into crystal grains with different crystallographic plane orientation, and is formed of polysilicon.

Differences of polysilicon and monocrystalline silicon performance in terms of physical nature. For example, in terms of mechanical properties, electrical properties, polysilicon are not as good as single crystal silicon. The polysilicon can be used as the raw material of the pulling of monocrystalline silicon.

Monocrystalline

Monocrystalline silicon can be regarded as the world's most pure substances, semiconductor devices in general require more than six nines purity silicon. There are two kinds of crystalline and amorphous silicon allotrope. Crystalline silicon is divided into the monocrystalline and polycrystalline silicon, and they are having a diamond lattice, the crystal is hard and brittle, having a metallic gloss, can be conductive, but the electrical conductivity is less than the metal, and increases with increasing temperature, with semiconductor properties.

Monocrystalline

Monocrystalline

LSI requirements are higher, the purity of the silicon must be nine 9. At present, people have been able to produce twelve purity single crystal silicon. Monocrystalline silicon is indispensable in modern science and technology of the electronic computer, automatic control system, the basic material. TV, computer, refrigerator, telephone, watches, cars, everywhere are inseparable from single crystal silicon material, monocrystalline silicon as one of the popularization of technology application materials, has penetrated into every corner of people's lives.

Monocrystalline solar panel converters Mars probe made of materials on Mars. Mars probe on Mars all the energy from the sun the detector rest during the day --- the use of solar panels to convert light energy into electrical energy storage, and scientific research activities in the evening. That is, as long as monocrystalline silicon, to place in the sun light, there is a source of energy.
Monocrystalline silicon raw materials essential for the space shuttle, spacecraft, satellites in space. Human beings made in the journey to conquer the universe, every step of progress, have a figure of silicon. The aerospace equipment most parts must monocrystalline basis. Leave monocrystalline silicon, the satellite will no energy, monocrystalline silicon, the space shuttle and the astronauts will not get in touch and Earth, monocrystalline silicon as the cornerstone of human scientific and technological progress, and made an indelible contribution to the conquest of space.

Monocrystalline silicon solar cells to be widely used. The high-purity single-crystal silicon is an important semiconductor material, the rapid development of photovoltaic technology and semiconductor micro inverter technology today, using monocrystalline silicon solar cells production can solar energy into light energy, achieved towards the start of the green energy revolution. Monocrystalline silicon solar cell characteristics: high photoelectric conversion efficiency, high reliability; advanced diffusion technology to ensure the uniformity of the conversion efficiency of the entire chip; 3. Using advanced PECVD film forming technology, the surface of the battery plated on a dark blue silicon nitride antireflection coating color uniformity and appearance; 4. Application of high-quality metal paste for back surface and electrode, ensuring good conductivity.

The monocrystalline broad range of applications and good prospects for the development of the Beijing 2008 Olympic Games will "green Olympics" as an important showcase for the world to show the use of single crystal silicon which is very important. Now, solar photovoltaic power plants abroad has reached a mature stage of the theory, is the transition to the stage of practical application, the use of solar cell  silicon single crystal will be spread to the worldwide market demand for self-evident.

Refining of metallurgical grade silicon is not difficult. Its preparation is mainly carbon reduction is used in the electric arc furnace is made of quartz sand. About 98-99% of the purity of the silicon so be restored, but the semiconductor industry with silicon must be highly purified (electronic grade polysilicon purity requirements of 11 9 solar battery grade only requires 6 9). In the purification process, a key technology of the reduction of trichlorosilane (Siemens method) have not yet mastered the absence of this technology, in the refining process more than 70% of polysilicon by chlorine emissions not only the cost of refining, and environmental pollution is very serious. China every year a large number of industrial silicon extracted from quartz, the price of $ 1 / kg exported to countries such as Germany, the United States and Japan, and these countries the industrial silicon is processed into high-purity crystalline silicon material to 46-80 dollars / kg sold solar charge controller companies in China.