Q. Which of the following semiconductors are used for LED manufacture?
1.Gallium Arsenide
2.Gallium Phosphide
3.Gallium Arsenide Phosphide
4.Indium Gallium Nitride
Select the correct answer using the codes given below:

[A] Only 1

[B] 2, 3 and 4

[C] 1, 3 and 4

[D] All

Answer: D
Notes:

Explanation: Materials commonly used to make LEDs are gallium arsenide (GaAs) and gallium phosphide (GaP). The main semiconductor materials used to manufacture LEDs are:

  • Indium gallium nitride (InGaN): blue, green and ultraviolet high-brightness LEDs
  • Aluminum gallium indium phosphide (AlGaInP): yellow, orange and red high-brightness LEDs
  • Aluminum gallium arsenide (AlGaAs): red and infrared LEDs
  • Gallium phosphide (GaP): yellow and green LEDs

Source: ForumIAS

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