Physics of Semiconductor Devices

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Fermi energies in intrinsic semiconductors

The effective densities of states at 300 K for several semiconductors are given below.

Nc

Nv

Eg

 Si (300 K)

2.78 × 1025 m-3

9.84 × 1024 m-3

1.12 eV

 Ge (300 K)

1.04 × 1025 m-3

6.0 × 1024 m-3

0.66 eV

 GaAs (300 K) 

 4.45 × 1023 m-3 

7.72 × 1024 m-3

1.424 eV

What is the fermi energy for intrinsic Si measured from the top of the valence band at 200 K?

Hint: Nc(T) = Nc(T=300)*(T/300)3/2.

Ef = eV