Interface states and Schottky barrier formation at metal/GaAs junctions

We report results of x-ray photoemission and cathodoluminescence spectroscopies studies of interface formation at metal-GaAs junctions. The results are interpreted by using a microscopic model of metal-semiconductor interfaces. Our low-temperature measurements and analyses show the validity of Schottky'S phenomenological description, thereby suggesting that metalinduced gap states and native defect mechanisms are not major factors in determining the Fermilevel energy at the low-temperature formed interface. Our room-temperature results show that a broad range of Fermi-level stabilization and the formation of two reaction-induced interface states are obtained upon metallization of GaAs ( 100) surfaces. These results strongly imply that the insensitivity of rectifying barrier height on metal work function results from metallizationinduced atomic relaxations at the interface.