Work function of sputter-formed Re-1% Pt. II. Recrystallized surface

The work function and surface composition changes occurring on a recrystallized surface of a sputter-formed Re-1% Pt alloy have been measured as a function of temperature. The work function was found to decrease with heat-induced segregation of Pt to the surface of the alloy. This behavior is the same as reported previously for a surface of the same material showing minimal recrystallization and can be explained by the Topping model of dipole formation. The dipole moment and polarizability of the surface Pt obtained from the combined data for both surfaces are (8.1 +- 1.5) x 10-30 C-m and (28.1 +- 6.3) A3, respectively. In cases where the surface Pt concentration was highly nonuniform, the derivative curve of the diode characteristic exhibited structure due to the patch effect. This structure in the data has been satisfactorily modeled by the superposition of two patches, each having a Gaussian work function distribution. Negative portions of the derivative curve were attributed to electron channeling and reflection