what is difference between Direct Band-gap and Indirect BG

[nikhilele]

I was asked this is ISRO's Interview for Post of SC
But i was not sure with answer:

"Direct valence electron directly jumps form Vbad to Cband"

and indirect same valence electron first reaches to energy level inbetween Vband and Cband and then it reaches to conduction band.

 

[THz]

Re: what is difference between Direct Band-gap and Indirect

For the direct band-gap, the k vector conserves.
For the indirect band-gap, the k vector changes.

 

[nikhilele]

I didn't get this answer the k vector to which i am familiar is wave vector.

which book will cover this topic....