Fermi level position at metal/semi-insulating - GaAs (1 0 0) interfaces studied by photoelectric techniques

Abstract

The Schottky barrier heights in Au/semi-insulating (SI) - GaAs (1 0 0) and Ni/SI - GaAs (1 0 0) contacts at room temperature have been determined from photovoltage and internal photoemission measurements. Both techniques give excellent agreement with each other. A small upward surface band bending of 0.141 eV for Au/SI - GaAs (1 0 0) and of 0.062 eV for Ni/SI - GaAs (1 0 0) has been determined. The interfacial Fermi level is found to lie at 0.772 eV and 0.690 eV below the conduction band minimum (CBM) at the Au/SI - GaAs (1 0 0) and Ni/SI - GaAs (1 0 0) interfaces, respectively. The accuracy of both photoelectric techniques suggests their beneficial use in future systematic studies on semi-insulating substrates in the study of Schottky barrier formation. © 1997 Elsevier Science Ltd.