Electron-induced secondary electron emission spectroscopy of surfaces

An introduction to the subject of secondary electron emission, characteristic energy loss and Auger electron spectroscopy is given, together with a brief survey of some relevant published work. An apparatus consisting of a 3600 retarding field spectrometer is described, together with the associated circuitry for the measurement of total yield, backscattering coefficient, the energy distribution, and its differential, of electron induced secondary electrons. Careful design of the analyser has enabled an energy resolution of better than 0.3% to be obtained and made possible the use of a wide range of incident electron angles and energies. Results are presented for the secondary electron yield and Auger electron spectra of a Zr/AI bulk getter. These show that the material has a low yield which may well make it suitable for gettering applications in electron beam tubes. High resolution Auger spectra of Pd, Ag, Su, Sb, Cu and Al are given showing fine structure previously seen only by workers using a cylindrical mirror analyser. In the case of AI, satellite peaks around the main peak can be interpreted by a plasmon gain and loss mechanism. Characteristic energy losses using a range of primary energies from 100eV to lkeV and incident angles from 0◦ to 60◦ have also been measured for the same metals, leading to the identification of surface, bulk and multiple plasma losses, and inter and intra-band transition losses. Extensive fine structure discovered in the low energy region of 0-2SeV for Pd, Ag, Cu and Al is associated with the preferential emission of conduction band electrons from states of high symmetry, rather than with plasmon gains