Photoelectron emission from SiO/sub 2/ surface oxidized on Si wafer

We have experimentally studied the relationship between photoelectron emission and surface current for SiO/sub 2/ layers on n-type Si. The photothreshold energy of untreated SiO/sub 2/ increased with increasing surface current from 5.05 to 5.3 eV, keeping a constant value up to about 20 pA of surface current. For the FAB (fast atom bombardment) treated specimen, the photothreshold energy decreased from 5.05 to 4.65 eV with increasing surface current. Such variations might be effected by surface conditions including surface states, surface structure, and electronic conduction in the surface.