High-Pressure Synthesis and Characterization of Cr-Doped Large Single-Crystal Diamonds

Diamond crystals doped with chromium were produced at 1400 degrees C and 5.8 GPa. The effect of Cr on the crystal morphology, nitrogen impurity content, and surface defects of diamonds grown on {111} and {100} planes has been studied in detail. The entry of the Cr impurity lattice in the Fe64Ni36-Cr-C and Fe64Ni36-Cr-Ti-C systems has also been analyzed. The results show that the addition of the proper amount of Cr in the FeNi-Cr-C system increases the growth rate of crystals. When Cr exists in the system, the N content decreases, and the crystallinity of the crystal increases. For the Fe64Ni36-Cr-Ti-C system, Cr is more easily doped into the synthesized crystals in terms of chromium-carbon and chromium-oxygen bonds, showing two valence states of Cr (VI) and Cr (III).