Extrinsic semiconductors (Boltzmann approximation)

The chemical potential μ of an extrinsic semiconductor is plotted as a function of temperature. At each temperature the chemical potential was calculated by requiring that charge neutrality be satisfied.

μ [eV]

T [K]

Nc(300 K) =

1/cm³  Semiconductor

Nv(300 K) =

1/cm³

Eg =

eV

Nd =

1/cm³ Donor

Ec - Ed =

eV

Na =

1/cm³ Acceptor

Ea - Ev =

eV

T1 =

K

T2 =

K

Once the Fermi energy is known, the carrier densities $n$ and $p$ can be calculated from the formulas, $n=N_c\left(\frac{T}{300}\right)^{3/2}\exp\left(\frac{\mu-E_c}{k_BT}\right)$ and $p=N_v\left(\frac{T}{300}\right)^{3/2}\exp\left(\frac{E_v-\mu}{k_BT}\right)$.

The intrinsic carrier density is $n_i=\sqrt{N_c\left(\frac{T}{300}\right)^{3/2}N_v\left(\frac{T}{300}\right)^{3/2}}\exp\left(\frac{-E_g}{2k_BT}\right)$.

$\log_{10}$ $n,p,n_i$ 
[cm-3]

T [K]

$\log_{10}$ $n,p,n_i$ 
[cm-3]

1/T [K-1]


See www.ioffe.rssi.ru/SVA/NSM/Semicond/index.html for the bandgaps and donor and acceptor states of various semiconductors.