# Homework Help: Electron and hole concentrations

1. Aug 14, 2010

### stagger_lee

Are the following formulas the correct solution to this question? Thanks in advance for any help!

1. The problem statement, all variables and given/known data

Write down equations for the electron and hole concentrations n and p in a semiconductor, in terms of $$N{c}$$ or $$N{p}$$, the Fermi level position $$E{f}$$ and the temperature, T.

2. Relevant equations

3. The attempt at a solution

n= $$N{c}$$exp[-($$E{c}$$-$$E{f}$$) / kT]

n=electron
$$N{c}$$=Number of energy levels, conduction
$$E{c}$$=Energy levels, conduction
$$E{f}$$=Fermi energy levels
k=Boltzmann's constant
T=Temperature

p= $$N{v}$$exp[-($$E{f}$$-$$E{v}$$) / kT]

p=holes
$$N{v}$$=Number of energy levels, valence
$$E{v}$$=Energy levels, valence
$$E{f}$$=Fermi energy levels
k=Boltzmann's constant
T=Temperature

Last edited: Aug 15, 2010
2. Aug 15, 2010

### nickjer

Looks fine to me, although I would have said $E_c$ is the energy level of the bottom of the conduction band. And vice-versa for $E_v$. Also, the $n$ is concentration and not number (although you never specify).

3. Aug 15, 2010

### stagger_lee

Thank you Nickjer, you've been a great help!