Analysis of diamond dislocations by Raman polarization measurement

Raman peaks with weak intensities at low wavelength were detected in dislocation areas of diamond substrates. Polarized Raman measurements were performed, and the origins of peaks were estimated. Based on the appearance of the Raman modes, the three peaks were estimated to be non-diamond owing to their structural asymmetries. Mapping measurements were carried out using one of the peaks and a small area of a high intensity region was estimated as the core of dislocation threading to the crystal surface. This method showed two dislocations on the surface, approximately 1.2 mu m apart. The imaging using the peaks will be a powerful tool for investigating the dislocations of diamond epitaxial layers.