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)/sca nning electron microscope hybrid system to ensure that even the smallest st ructures 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 e lectron beam. The achievable resolution of this NF-CL analyses has been imp roved to approximately 50 mn. ln addition, it was possible to determine ele ctronic properties such as the local diffusion lengths by keeping the posit ion of the SNOM probe constant and scanning the electron beam. Using this t echnique, distributions of defects within small diamond grains became visib le without any sample preparation. Dislocations, hydrogen plasma induced de fects, and nitrogen impurities were separated on a H post-treated MW-CVD di amond single crystal. Clusters of the 575-nm luminescence system were detec ted. A shift from blue to green of the Band-A emission depicted a dislocati on. (C) 2001 Elsevier Science B.V. All rights reserved.