Influence of non-diamond carbon phase on recombination mechanisms of photoexcited charge carriers in microcrystalline and nanocrystalline diamond studied by time resolved photoluminescence spectroscopy

Recombination processes of photoexcited charge carriers in as-grown micro/nanocrystalline diamond films containing various amounts of non-diamond carbon phase were studied by time resolved photoluminescence spectroscopy. The photoluminescence was found to be strongly sensitive to diamond morphology and concentration of non-diamond carbon phase. We found two photoluminescence components differing in decay rates (nano/microsecond time scales) and in response to ambient air pressure, temperature and excitation light parameters. Experimental data form the basis for interpretation of recombination paths of photoexcited charge carriers in micro/nanocrystalline diamond films in dependence on their morphology and non-diamond carbon phase content.