Soft-x-ray-induced secondary-electron emission from semiconductors and insulators: Models and measurements

摘要: Secondary-electron energy distribution curves (EDC's) and the total secondary-electron yields relative to such for gold have been measured seven semiconductors which electron-electron scattering losses within emitter were considered dominant nine insulators (alkali halides) electron-phonon expected be in transport process. The spectra excited by Al-$K\ensuremath{\alpha}$ (1487 eV) photons from evaporated dielectric films (of about 0.3 \ensuremath{\mu} thickness) on conducting substrates with an electrostatic hemispherical analyzer of 0.03-eV resolution. Some photoemitters appreciably narrower distributions higher than has gold; CuI CsI EDC widths at half-maximum one-third that gold, yield values 11 30 times greater. FWHM 4 eV 0.50 electrons per normally incident photon, respectively. shapes EDC's found essentially unchanged photon excitation 0.1-10-keV region. Strong structural features appear only alkali halide EDC's, it is proposed these are mainly result single-electron promotion secondaries valence band plasmon deexcitation. A relatively simple model x-ray photoemission developed assumes direct photoelectron Auger-electron "primaries" mechanism, accounts both Free-electron conduction-band descriptions assumed. theoretical experimental satisfactory agreement.