Why Don't Silicon Diodes Emit Light in LED Applications?

[uzair_ha91]

Why don't silicon diodes emit light?
Attempt:
No idea. However, I do know that gallium arsenide is used as a semiconductor in LEDs.

 

[mgb_phys]

Why don't silicon diodes emit light?.

They do - it's a big problem building astronomical cameras, every time you clock a pixel you get some light.

It's not very efficent though compared to GaAS