I think semiconductors (such as most solar cells) do not act as ideal black bodies. Thermal excitation (what temperature required?) can move electrons into the

I think semiconductors (such as most solar cells) do not act as ideal black bodies. Thermal excitation (what temperature required?) can move electrons into the conduction band and when the electron relaxes it emits a photon corresponding to the band gap. I looked for a good article, but didn't find anything. There was one relevant comment in the first article I skimmed that said "semiconductors do not behave remotely close to a blackbody": sounds authoritative but the comment was on stack-overflow so hard to judge its correctness!