Indirect band gap semiconductor doubt

[munna007]

indirect band gap semiconductor doubt

its said that indirect band gap semiconductors like silicon and germanium are not used as a light sources because they have more non-radiative recombinations rather than radiative ,which inturn decreases efficiency of optical source.


but i want to understand how indirect band gap materials produce non-radiative photons.

i have studied many books like keiser , senior on optical fibre .those all are not explanatory on this ...also googled for this ,but not helped from there...


hoping for help here...thanks...love to all...

 

[MATLABdude]

The answer is that they do not produce non-radiative photons. There are a few radiative photons produced, but the majority of recombinations will result in phonons (lattice vibrations) and heating of the semiconductor. My semiconductor physics is a little rusty, but I think that Auger recombination is the phrase you're looking for.

The book I used for my condensed matter physics (which covered this) was Kittel's Introduction to Solid State Physics.