Electron or Hole: Which Has the Greater Effective Mass?

[preitiey]

In case of a semiconductor, the position of Fermi level in between valence band and conduction band doesn't lie in the middle of the band gap due to the difference in the effective masses of holes and electrons. so, whose effective mass is more- electron or hole?

 

[preitiey]

I don't understand here one thing. Holes are created when electrons move from their respective places creating vacancies. Then how can we consider the mass of a vacancy? I mean it should be negligible

 

[#neutrino]

Holes are not physical particles they are imaginary

 

[DrDu]

Electrons near the top of a band have a negative effective mass. If the band is nearly full, we can describe the absence of such an electron as the presence of a hole with opposite charge and mass.