Density of states at Fermi level for metal vs semiconductor

[aaaa202]

We are doing spectroscopy on some semiconductors covered by a layer of Aluminium.
My professor says it might be a challenge for to see the valence band structure of the semiconductor because the metal has a high density of states at the fermi level. Does this make sense to you? Does a metal have a high density of states compared to a semiconductor? If so, why?

 

[voila]

In a semiconductor, the Fermi level sits in the bandgap, whereas in a metal, it does inside a band (this is, actually, what drives their behaviour). Even different orbitals (different bands) can be at the Fermi level for metals. This high density of states is what allows the "electron sea".