Nitrogen and group-IV (Si, Ge) vacancy color centres in nano-diamonds: Photoluminescence study at high temperature (25 °c-600 °c)

Abstract

Raman scattering and photoluminescence measurements have been carried out on nano-diamonds containing Nitrogen-vacancy (NV-), Silicon-Vacancy (SiV-) and Germanium-vacancy (GeV-) synthesized by high pressure and high temperature method. Optical zero-phonon-line transition of these negatively charged centres were measured from room temperature up to 600 °C under air. The results show that all nano-diamonds are stable at this temperature range and spectra are reproducible for heating and cooling cycles. Thermal behaviors of linewidth and zero phonon line, for SiV- and GeV- centres, are well described by the second-order electron-phonon interactions involving two-phonon and elastic processes.