First principles calculations of the adsorption of single group III and group V atoms on Si(0 0 1)

We have performed first principles total energy calculations to determine the adsorption site of single group III (Al, Ga, and In) or group V (As and Sb) adatoms on Si(0 0 1). Two different binding configurations are found for group III elements. In the first one, the adatom is in a three-fold position between two Si dimers, while in the second one, it is on top of a second layer Si atom (M site). For Al and In we found that the two binding positions have the same total energy. In the case of Ga, the M site is slightly more favorable by 0.17 eV/adatom. A single adsorption site is found for group V elements, and it is located almost on top of a Si dimer. In all cases, Si dimers not involved in the bonds are barely affected.