FORMATION ENERGY, LATTICE-RELAXATION, AND ELECTRONIC-STRUCTURE OF AL SI/GAAS(100) JUNCTIONS/

We investigated the energetics as well as the structural and electroni c properties of chemically abrupt AlGaAs(100) and engineered Al/Si/GaA s(100) Schottky diodes with 2 monolayers of Si using the ab initio pse udopotential approach. Results for the atomic relaxation at the interf ace, its influence on the Schottky barrier, and the dependence of the formation energy on the As and Ga chemical potentials are presented. W e show that a reversal in the relative stability of the As- and Ga-ter minated junctions occurs within the experimentally accessible range of the As and Ga chemical potentials, for both Al/GaAs and Al/Si/GaAs in terfaces. This reversal could explain the role played by the excess ca tion and anion flux in the fabrication of tunable Al/Si/GaAs(100) Scho ttky diodes. [S0163-1829(98)04716-X].