Temperature dependence of germanium vacancy centers in high-quality diamond after 300 keV ion implantation

In this work, the temperature dependence of diamond GeV centers that were formed by germanium (Ge) ion implantation and annealed in a hydrogen atmosphere at 1000 °C was investigated by photoluminescence spectroscopy. It was found that the intensity of the GeV centers had a thermal quenching effect with the increase in temperature, and the activation energy was fitted at 62.32 meV. Then, the laser power dependence was mainly dependent on radiative recombination so that the diamond GeV center intensity increased with the laser power. Furthermore, the electron-phonon coupling and thermal softening effect were found between Ge ions and vacancies chemical bonds, which made the GeV center peak position red shift with the increase of temperature. Finally, the FWHM of the diamond GeV center exhibited both homogeneous (Lorentzian component) and inhomogeneous broadening (Gaussian component) at 80-280 K, indicating that the Lorentzian component was dominant in the FWHM of the GeV center.