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How does led chips emits lights

Nanjing Huiguang Lighting Co.,Ltd | Updated: May 17, 2018

But what do LEDs consist of?

Basically, an LED consists of several layers of semiconductor compounds. Semiconductors, such as silicon, are materials whose electrical conductivity lies between that of conductors, such as the metals silver and copper, and non-conducting materials (insulators) such as PTFE or quartz glass. The conductivity of semiconductors can be greatly influenced by the specific introduction of electrically effective external substances (by means of a process known as doping). The different semiconductor layers together form the LED chip. The type of structure of these layers (various semiconductors) has a crucial bearing on the luminous yield (efficiency) and light colour of the LED.


 


If a current flows through the LED in the flow direction (from anode + to cathode –), light is created (emitted).


 


The n-doped layer is prepared by the incorporation of foreign atoms so that there is a surplus of electrons. In the p-doped layer, there are only a small number of these charge-carriers. This produces so-called electron holes (band gaps). When a voltage (+) is applied across the p-doped layer and n-doped layer (-), the charge-carriers move towards each other. At the pn junction, recombination takes place (where oppositely-charged particles combine to form a neutral entity). This process releases energy in the form of light.