Ballistic-electron-emission microscopy and spectroscopy of GaP(110)-metal interfaces

Ballistic-electron-emission-microscopy (BEEM) studies of Mg, Ni, Cu, Ag, and Au films on cleaved n-type GaP(110) show uniform Schottky-barrier heights across the surfaces, which varied from 1.02 eV for Mg to 1.41 eV for Au. BEEM images reveal areas of sharp current variations (contrast) that coincide with topographic gradients on the metal surfaces. Deduced Schottky-barrier heights depend on the transport model; a 5/2 power-law dependence of the BEEM current on applied voltage results if nonclassical transmission across the interface is included. © 1991 The American Physical Society.