Uni1, Example 1

SEMITIP V6, Uni1, Example 1: n-type GaAs(110)

Click here for input/output files for Example 1

This example illustrates a simple band bending computation for n-type GaAs doped at 10¹⁸ cm^-3, assuming a contact potential of 0 eV and a sample-tip voltage of 1 V. The semiconductor is thus in depletion. Intrinisic surface states are present just above the conduction band edge (lines 18-21 of the FORT.9 input file), but they play no role in the solution.

Output to FORT.11 gives the electrostatic potential energy (column 2) vs. the z-distance through the vacuum and semiconductor (column 1). When plotted, the potential appear as:

We see that nearly half of the applied voltage bias is dropped in the semiconductor. This relatively large band bending in the semiconductor is reduced for a three-dimensional case, as in Example 1 of Uni2.