Abstract
Optical absorption evolution is studied for 150–800 μm thick diamond films grown by microwave plasma enhanced CVD technique and annealed in vacuum at temperatures 900–1600 °C. A noticeable internal degradation (darkening) of the films takes place at T > 1300 °C. Changes in the concentration of different CHx groups are revealed from the IR spectra starting at T > 1000 °C. Up to 25% of the total amount of hydrogen in as-grown films is found to be unbonded. An interesting effect of reduced absorption in UV range due to the formation of new C–H bonds by reaction of primarily unbonded hydrogen is observed. The diamond darkening correlating with the bonded hydrogen loss process, is ascribed to the appearance of a graphite-like phase (being under a high stress) presumably at grain boundaries, that is revealed by the appearance of a specific absorption peak in UV spectra.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: 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.