SiV Color Centers in Si‐Doped Isotopically Enriched 12C and 13C 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 CH4/H2 mixtures using methane enriched to 99.96% for either 12C or 13C isotopes, while the Si doping was performed by adding a small percentage of silane SiH4 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 12C diamond at T = 5 K, exhibits a blue shift of 1.78 meV, to 736.1 nm in 13C 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 13C diamond. Besides the charged SiV− center, the absorption of the neutral SiV0 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.