1) Go to Energy Band Creator
2) Set:
     Depth = 400 eV
     Separation = .500 nm
     Number of Atoms = 2
3) Click Find Energies
4) Lower the Depth by a small increment (eg. .020 nm)
5) Click Find Energies
6) Repeat Steps 4 & 5 until Depth = .200 nm
7) Raise the Number of Atoms by 1 or 2.
8) Click Find Energies
9) Repeat Steps 7 & 8 until Number of Atoms = 20