Question

8. Silicon is not suitable for Light
Emitting Diode (LED) because it is
1)An indirect band gap semiconductor
2)A direct band gap semiconductor
3)A wide band gap semiconductor
4)A narrow band gap semiconductor​

Answer 1

Answer:

1) an indirect band gap semiconductor

Explanation:

As in indirect semiconductor gap,  electrons have different momentum. To   support momentum conservation law they need to do something with this  momentum, which is emission of photons. While in direct gap semiconductors gap and electron pair momentum can be zero and they are able to combine with no emission of light.