Electron microscopy; proceedings of the Electron microscopy; proceedings of the Stockholm Conference, September, 1956 electronmicrosco00euro Year: 1957 Fig. 1. Reflection electron micrographs of a type 1 diamond cleavage surface, m^ ~ 2000 : m^ 250 Fig. 2. Reflection electron micrograph of a type II diamond cleavage surface. /«i ~ 3000 : /^u ~ 400 ultra violet absorption. The diamonds were cleaned in nitric acid, followed by distilled water. A layer of silver about 500 A thick was evaporated onto the surface to prevent charging of the specimen in the electron beam. The examination was carried
Electron microscopy; proceedings of the Electron microscopy; proceedings of the Stockholm Conference, September, 1956 electronmicrosco00euro Year: 1957 Fig. 1. Reflection electron micrographs of a type 1 diamond cleavage surface, m^ ~ 2000 : m^ 250 Fig. 2. Reflection electron micrograph of a type II diamond cleavage surface. /«i ~ 3000 : /^u ~ 400 ultra violet absorption. The diamonds were cleaned in nitric acid, followed by distilled water. A layer of silver about 500 A thick was evaporated onto the surface to prevent charging of the specimen in the electron beam. The examination was carried out using the Metropolitan Vickers EM3 electron micro- scope modified for use in reflection (4). Reflection electron micrographs typical of dia- monds of the two types are shown in figures I and 2. The conchoidal nature of the type I cleavage and the much smoother nature of the type II cleavage are apparent. The surface roughnesses may be estimated from measurements on the micrographs. The type I cleavage surfaces are so rough, however, that it is difficult to give an accurate value of the change in height which corresponds to a particular shadow, since the local slope of the surface on which the shadow falls is not known. Certainly, there are fairly abrupt changes in height of a micron or more on the part of the surface shown in figure I. Other parts of the surface of this diamond were consider- ably rougher and were too rough for examination by reflection electron microscopy. The type II sur- face shown in figure 2 is considerably smoother. The steps seen here are probably all less than 1500 A in height, and many of the regions between the larger steps are flat to within 300 A. Other regions of type II diamond cleavage surfaces are similar in appear- ance, but there are occasional large steps of perhaps a micron in height. These large steps differ from those on type 1 diamonds in that they separate relatively smooth regions. The lines running in the direction A on figure 2
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