Abstract
Detailed study of the luminescence of multiple brown CVD diamonds was performed. It has been found that the well-known optical center with zero-phonon line at 468 nm is a characteristic of brown color. It has been found that the defects responsible for 468 nm center are located within brown striations suggesting close relation of the 468 nm center and the vacancy clusters. Simultaneous reduction of the intensity of 468 nm center and brown color during annealing support the assumption of their close relation. Identical spectroscopic parameters of the 468 nm center and the radiation center with ZPL at 492 nm suggest that the former relates to an intrinsic defect probably containing vacancies. The distribution of intensity of the 468 nm center in some brown diamonds follows the distribution of the NV− center while being opposite to that of the NV0 center and the dislocation-related A-band. This observation suggests the negative charge state of the 468 nm center. Due to its high luminescence efficiency, the 468 nm center can be used as a highly sensitive indicator of the traces of vacancy clusters. We found that the 468 nm center is detected practically in every as-grown CVD diamond including colorless CVD diamonds of high structural perfection and high purity.
Highlights
Common color of natural diamond is brown
In brown CVD diamonds, no luminescence center has been ascribed to brown color too. In this communication we report the results of spectroscopic studies of the luminescence center with zero-phonon line (ZPL) at a wavelength of 467.7 nm at liquid nitrogen temperature (LNT), which is one of the most common and specific optical center of brown CVD diamond
We have found that 468 nm center is closely related to vacancy clusters and its intensity can be used as a measure of the presence of brown color
Summary
Common color of natural diamond is brown. Brown color is common component for as-grown CVD diamond. For many applications, including jewelry, optics, electronics and medicine, the brown color is a feature downgrading the quality of diamond. In brown CVD diamonds, the spectral position of the broad bands is shifted to wavelengths of 380 nm and 520 nm respectively [3,6,7]. These differences raise the question of whether the vacancy clusters in natural and CVD diamonds are of the same structure [2,8]. Much shorter growth time of CVD diamonds than natural diamonds can limit the diffusion of vacancies and, the vacancy clusters in CVD diamonds are expected to be smaller. A conclusion was made that only small-size vacancy clusters are optically (absorption) active
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
