The basic properties of point defects, such as local geometries, positions of charge transfer levels
and formation energies,
have been calculated using
density functional theory, both in the bulk and on the (110) surface of InP, InAs, and InSb.
Based on these results we discuss
the electronic properties of bulk and surface defects,
defect segregation and compensation.
In comparing the relative stability of the surface and bulk defects, it is found that the native defects generally have higher formation energies in the bulk.
From this it can be concluded that at equilibrium there is a considerably larger fraction of defects at the surface and under non-equilibrium conditions defects are expected to segregate to the surface, given sufficient time. In most cases the charge state of a defect changes upon segregation, altering the charge carrier concentrations.
The photo-thresholds are also calculated for the three semiconductors and are found to be in good agreement with experimental data. |