How to experimentally determine whether have adirect or indirect semiconductor?

[martiniux]

Suposse you have a material you are told is semiconductor, but don't know any more history about the material. What experiment(s) can be performed in order to find out if your material is direct or indirect?

 

[ZapperZ]

Someone who has more knowledge than me in optical spectroscopy can answer this. One of the experiments that I know of where one can determine if something has a direct or indirect band gap is FFT-IR - Fast Fourier Transform Infra-red. That would make sense because you can induce the phonon modes to provide the momentum necessary for an indirect transition.

But like I said, someone more familiar with optical spectroscopy should be the one to address this.

Zz.