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dervast
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Hi i was reading yesterday in a semiconductor lessons that the Si is not suitable for creating light.. Do u know why is this happening?
This is clearly explained in the article I linked. An indirect bandgap is one when the VB maximum and CB minimum have different crystal momenta. For an electron to go from the first to the second, it needs a considerable change in momentum. A photon does not have enough momentum to make this change possible; so a photon can not facilitate this transition.dervast said:Thx a lot but how can u explain me that optical transitions in Si are not propable to occur? How the indirects bands affect these transitions
Silicon (Si) is not suitable for creating light because it is an indirect bandgap semiconductor. This means that when an electron is excited from the valence band to the conduction band, it does not release energy in the form of light. Instead, the electron releases energy in the form of heat, making Si inefficient for producing light.
While Si is not suitable for creating light on its own, it can be used in combination with other materials to produce light. For example, Si is commonly used as a substrate in light-emitting diodes (LEDs) where other materials, such as gallium nitride, are used to produce the actual light.
Another reason why Si is not suitable for creating light is its high refractive index. This means that when light travels through Si, it is bent at a sharper angle, making it difficult for the light to escape and be emitted. This reduces the efficiency of Si in producing light.
Some commonly used materials for producing light include gallium nitride, indium phosphide, and gallium arsenide. These materials have direct bandgaps, which allow for more efficient light emission. They are also commonly used in combination with Si for various applications.
While Si is not commonly used for producing light, researchers are constantly exploring new ways to utilize its unique properties. One potential use is in silicon photonics, where Si is used to manipulate and control light for data communication and processing. However, more research and development is needed in this field before it can become a practical application.