513.001 Molecular and Solid State Physics

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Wolfram Alpha

Physical
Constants

Periodic System
of Elements

      

Chemical potential in a semiconductor

The concentrations of electrons and holes in silicon are given by

     

Where the effective densities of states at 300 K are Nc = 2.78 × 1025 m-3 and Nv = 9.84 × 1024 m-3. The gap of silicon is Eg = 1.12 eV.

a) For intrinsic (undoped) silicon at room temperature, what would be the concentration of electrons and holes?

b) For temperatures near room temperature, will the chemical potential increase or decrease with the temperature? Why? What does this have to do with the effective density of states?