Lateral scan profiles of the recombination parameters correlated with distribution of grown-in impurities in HPHT diamond

• Diamond single crystals synthesized by HPHT technology were examined.
• Profiling of photoconductivity transients and time resolved photoluminescence was made.
• EPR, FTIR spectroscopy and microscopy imaging have been combined.
• Nitrogen defects and nickel precipitates are related to recombination parameters.
• Changes of radiative and non-radiative recombination lifetime have been resolved.

The profiling of the microwave probed photoconductivity transients and of the time resolved photoluminescence spectra has simultaneously been performed on the synthetic diamond wafer samples in order to clarify correlation of the distribution of the grown-in defects and carrier radiative and non-radiative recombination channels. The wafer samples were sliced from the diamond single crystals, synthesized by the high pressure and high temperature (HPHT) technology using the Ni–Fe liquid solvent/catalyst system. To estimate the microscopic characteristics of the grown-in defects, the EPR spectroscopy has been carried out. The changes of carrier lifetime, ascribed to the radiative and non-radiative recombination, have been resolved. The correlation between the parameters extracted from the absorption spectra and recombination characteristics has been obtained. The prevailing grown-in point defects, associated with neutral and charged nitrogen impurity complexes as well as the pairs of nitrogen atoms on neighbouring sites, and the nickel precipitates have been unveiled.