Direct Observation of Solid Surfaces at High Resolution by Reflection Electron Microscopy

Abstract

A standard commercial transmission electron microscope has been modified for the direct examination of solid surfaces at high resolution by reflection. The geometry, resolution, contrast and depth of focus of the images obtained are briefly discussed. An investigation has been made of the types of specimen which may usefully be studied by the method. It is pointed out that its main value lies in the examination of very flat surfaces, e.g. high mechanical and electropolish, cleavage faces, and surfaces on which there are isolated features, e.g. cleavage and growth steps, overgrowths, etc., and features too large to be within the depth of focus of the optical microscope or within the range of transmission electron microscope replica methods. Among the specimens studied are cleavage features on zinc single crystals and mica, growth features on silicon carbide crystals, surface damage (scratches) produced by sliding. It is suggested that the method may be valuable for the examination of some biological specimens where replica methods are inappropriate.