# Potential Barrier for different types of junctions

1. Jun 22, 2014

### Joseph8022

Hi all,
How I can calculate the Potential Barrier when we have a metal- semiconductor, metal- metal, or p-n junction ? Can I calculate the Potential Barrier by using a workfuncion?

2. Jun 22, 2014

### Simon Bridge

Welcome to PF;
The exact shape of the barrier is usually modeled using self-consistent calculations - depending on the exact structures being modeled.

The height of the barrier can sometimes be worked out from the band-mismatch.

3. Jun 22, 2014

### Joseph8022

Thank you! I have a lot of formulas for calculating the Potential Barrier, and I get confused with them. I'm not sure about it ! In p-n junction, can I find the Potential Barrier by finding the difference in Fermi energy of the p and n-type junction? What about if I have a metal-semiconductor junction ?

4. Jun 22, 2014

### Simon Bridge

You should be able to make out what your formulas are about by sketching the band profiles next to each other.
At the junction you'd get some band bending irl.

5. Jun 23, 2014

### Joseph8022

Thank you, again ! I need to know the formula for calculating the Potential Barrier in p-n junction, please, write it down if you know it.

6. Jun 25, 2014

### Simon Bridge

In general?

It's a self-consistent calculation using Poisson's equation to work out the band bending and the Schrodinger equation to work out the charge distribution. Rinse and repeat. What level education are you doing this at? Did you have a specific p-n junction in mind?