Schottky-barrier height of ideal metal contacts to GaAs

The Schottky-barrier height φB of ideal (no interfacial oxide) contacts to GaAs has been measured for a diverse group of eleven metals, Cu, Pd, Ag, Au, Al, Ti, Pb, Bi, Ni, Cr, and Fe, by using current-voltage and capacitance-voltage techniques. The contacts were formed by metal evaporation in ultrahigh vacuum onto clean (100) surfaces of both n-type and p-type GaAs. For n-type contacts φB ranged from 0.96 to 0.72 eV, in the metal order listed above; for p-type contacts φB ranged from 0.45 to 0.62 eV. No simple correlation was found between φB and metal work function nor between φB and the chemical reactivity at the metal-GaAs interface.