Temperature dependence of optical centers in Ib diamond characterized by photoluminescence spectra

Abstract The optical properties of defects in Ib diamond prepared by Chemical Vapor Deposition (CVD) and High Pressure High Temperature (HPHT) methods are studied by photoluminescence in a temperature range of 77– 297 K. The temperature dependence of color centers in diamond of 2.65 eV center, NV0, NV-, SiV-, 3H is studied. The zero-phonon line (ZPL) shift, intensity and full width at half maxima (FWHM) have a strong temperature dependence. The study shows that, due to the expansion of the lattice and the enhancement of the electron-phonon coupling strength, the ZPL shift can be described by the modified Varshni model which shows great potential in temperature sensing. The FWHM of ZPL matches a cubic function of temperature, this model can be employed to well describe the broadening of ZPLs in the defect-rich diamond. And the thermal quenching of absolute PL intensity can be described by the Arrhenius equation. Meanwhile, the difference of variable PL signal between CVD and HPHT samples is analyzed.