Pressure Dependence of the Schottky Barrier Heights in Al/AlGaAs Junctions

The influence of hydrostatic pressure up to 8 kbar on the barrier height of epitaxially MBE-grown Al on AlGaAs metal-semiconductor junctions is reported. The pressure change of the Schottky barrier on n-type AlGaAs is the same as that of the energy gap (for both direct and indirect-gap AlGaAs compositions), while for p-type AlGaAs it is negligible. This result is in direct conflict with a class of models of the Schottky barrier formation based on a concept of a semiconductor neutrality level alignment with the metal Fermi level.