Abstract
The inhomogeneous spatial distribution of the efficiency of excitation of visible luminescence by ultra-violet quanta, which are absorbed by intrinsic processes resulting in the production of excitons, has been measured for a semiconducting diamond. The large-scale distribution of internal mechanical strain in this specimen, revealed by the birefringence pattern, shows a close correlation with the spatial variations in the efficiency of luminescent emission, although fine striations present in the birefringence pattern are not resolved in the distribution of the luminescence. An upper limit of 50μm has been established for the distance over which energy transfer takes place at 295°K between the point of absorption of the ultra-violet quanta and the visible luminescence centres. The appearance of the birefringence pattern suggests that the strain fields are due to dislocations, and the hypothesis is advanced that the luminescence originates at defect centres connected with the dislocations.