SiV Color Centers in Si‐Doped Isotopically Enriched 12 C and 13 C CVD Diamonds

The effect of isotopic modification of diamond lattice on photoluminescence (PL) and optical absorption spectra of ensembles of SiV − centers was studied. Thin epitaxial diamond layers were grown by a microwave plasma CH 4 /H 2 mixtures using methane enriched to 99.96% for either 12 C or 13 C isotopes, while the Si doping was performed by adding a small percentage of silane SiH 4 into the plasma. Temperature dependent SiV − ZPL spectra in absorption were measured at 3–80 K to monitor the evolution of the ZPL fine structure. It is found that the SiV − ZPL at 736.9 nm observed in PL for 12 C diamond at T  = 5 K, exhibits a blue shift of 1.78 meV, to 736.1 nm in 13 C diamond matrix. Narrow ZPL with the width (FWHM) of 0.09 meV (21 GHz) was measured in absorption spectra at T  = 3–30 K in the Si‐doped 13 C diamond. Besides the charged SiV − center, the absorption of the neutral SiV 0 defect at 946 nm wavelength has also been detected. From changes observed in SiV − phonon band structure in PL with isotopic modification, the band at 64 meV was confirmed to be a local vibration mode (LVM) involving a Si atom.