Mention the important considerations required while fabricating a p-n junction diode to be used as a Light Emitting Diode (LED). What should be the order of band gap of an LED if it is required to emit light in the visible range ?

Mention the important considerations required while fabricating a p-n

1.	Mention the important considerations required while fabricating a p-n junction diode to be used as a Light Emitting Diode (LED). What should be the order of band gap of an LED if it is required to emit light in the visible range ?
Answer» Solution :The p-n junctiorn diode, which emits spontaneous radiation when forward biased, is known as the "LIGHT emitting diode" or LED. The semiconductorused in LED is chosen according to the required wavelength of emitted radiation. The visible light is from 0.45 um to 0.7 um and corresponding PHOTON energy is between 2.8 eV to 1.8 eV. Therefore, the least BAND gap of the semiconductor to be used in LED, in order to have the emitted radiation to be in the visible REGION, should be 1.8 eV. Phosphorous doped gallium ARSENIDE and gallium phosphide are two such suitable semiconductors.

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Mention the important considerations required while fabricating a p-n junction diode to be used as a Light Emitting Diode (LED). What should be the order of band gap of an LED if it is required to emit light in the visible range ?

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