Near-field cathodoluminescence of nanoscopic diamond properties

Near-field detection cathodoluminescence (NF-CL) analyses on MWCVD diamond has been carried out in a scanning near-field optical microscope (SNOM)/scanning electron microscope hybrid system to ensure that even the smallest structures with modified material properties can be evaluated. The CL signal is detected directly with the SNOM tip above the recombination center while the sample is irradiated simultaneously as well as homogeneously with an electron beam. The achievable resolution of this NF-CL analyses has been improved to approximately 50 nm. In addition, it was possible to determine electronic properties such as the local diffusion lengths by keeping the position of the SNOM probe constant and scanning the electron beam. Using this technique, distributions of defects within small diamond grains became visible without any sample preparation. Dislocations, hydrogen plasma induced defects, and nitrogen impurities were separated on a H post-treated MW-CVD diamond single crystal. Clusters of the 575-nm luminescence system were detected. A shift from blue to green of the Band-A emission depicted a dislocation.