Electron stimulated electron emission from solid surfaces

Wright, Barry

Abstract

The topic of electron stimulated secondary electron emission is introduced in relation to studies in surface physics. In addition, some of the more recent literature in this subject is reviewed and critically appraised.
An apparatus for high resolution energy analysis of low energy (0-2keV) secondary electrons is described, along with its associated circuitry. Additional experimental features are discussed enabling both scanning electron microscopy and quantitative Auger electron spectroscopy to be used in the experimental apparatus. Ultra-high vacuum techniques (giving 10-10 torr pressure) enabled the observation of clean surfaces for many hours, before contamination ensued.
The results presented relate to several problems in Auger electron spectroscopy and affiliated techniques. The problems of quantifing Auger spectroscopy are discussed and the cesium on gold system is investigated for quantification purposes. Calibration curves for this system are given. Also, the strong surface reactivity of zirconium is investigated using Auger spectroscopy. Zirconium is now in wide use as a bulk gettering material although little is known about its pumping action. The presented results shed more light on this topic. The production and analysis of temperature-resistant low secondary yield metal blacks, indicate a strong preference for platinum black coated surfaces in many technological applications. Also, observations of the anomalous 'free-electron like' behaviour of antimony are made, using the technique of electron energy loss spectroscopy.
Perhaps the most important results, relate to characteristic slow secondary electrons originating from 'very clean' magnesium and aluminium surfaces. Much of the recent literature in this area is shown to be inaccurate by these new experimental data. Also, a new interpretation of these data indicates that high-energy band structure can influence slow secondary electron energies. The interpretation enables critical point energies to be determined accurately. In addition, this slow peak spectroscopy is shown to be capable of greater sensitivity to surface contamination than Auger electron spectroscopy.

Citation

Wright, B. (1974). Electron stimulated electron emission from solid surfaces