Room Temperature PL Characterization of Polycrystalline Diamond Prepared by HPHT

Diamond polycrystalline composites with some different elements were prepared by HPHT (high pressure and high temperature). The dependence between emission energy and excitation energy was characterized by PL technique. The results showed that the photoluminescence of diamond polycrystalline composites was not affected by additives, only related to the excitation. The emission wavelengths of composites decreased with excitation, at the same time, emission peaks shifted to high energy region and the peak width at half-height decreased relatively. The energy of emission had a linear relationship with that of excitation. The emission band peak location shifted from 1.57 (790nm) to 1.97eV (628nm) as the excitation wavelength changed from 2.34 (530nm) to 2.95eV (420nm). Emission intensity decreased linearly with the decrease of excitation energy intensity. However, this linear dependence disappeared as excitation wavelength was below 400nm.