Energy-distribution studies of photoexcitation in photofield emission

Total energy distributions of the photocurrent in photofield emission from tungsten have been measured for $s$- and $p$-polarized light. The results show that for photon energies below 3.5 eV the dominant mechanisms of photoexcitation are the surface photoeffect and the indirect bulk photoeffect. In the photofield-emission configuration the surface and indirect bulk distributions can be separated by suitably choosing the polarization and angle of incidence of the illumination.