Cathodoluminescence in Deformed Diamond

Abstract

WE describe here, for the first time, changes in the cathodoluminescence of diamond, caused by deformation. Fig. 1—a scanning electron micrograph—shows part of a polished (100) surface of a diamond. This surface had been prepared for another experiment by polishing in the [001] direction with 0–1 µm powder, and then in the [010] direction with a nominal 4–8 µm powder. The surface damage shown in Fig. 1 appeared during polishing with the coarser powder. The area is approximately square in outline with sides about 30 µm long, but two of the four sides appear fore-shortened, as the surface was tilted in the microscope to bring out detail. The damage is similar to the ring cracks produced on diamond surfaces by loading them with a ballbearing. An analysis of these ring cracks^1,2 shows that the damage consists primarily of a cone crack, spreading outward and downward from the surface, which is held open by debris when the load is removed. The stone is thus left in a state of elastic strain, particularly in the region within the surface crack.