OPTICAL MODULATION OF LOW-ENERGY-ELECTRON TRANSMISSION - ZNO

When low-energy (0-100 eV) electrons are incident on a solid surface, some are transmitted into the bulk of the solid where they can be readily measured. This paper reports measurements made on ZnO of both this transmitted current and the optically modulated component of this transmitted current which arises when chopped light is incident on the surface. Both of these experimental quantities have a pronounced dependence on incident electron energy. At lower incident electron energies (1-21 eV), this dependence is related to the conduction-band density of states for ZnO. The cause of the electron energy dependence at higher incident electron energies (22-91 eV) is not yet understood, but several possibilities are suggested. © 1979 The American Physical Society.