question_answer

For LED’s to emit light in visible region of electromagnetic light, it should have energy band gap in the range of:                                                         [JEE ONLINE 12-04-2014]

A) eV to 0.4 eV

B) 0.5 eV to 0.8 eV

C) 0.9 eV to 1.6 eV

D) 1.7 eV to 3.0 eV

Correct Answer: D

Solution :

[d] Energy band gap range is given by,

For visible region