Properties of boron-doped HPHT diamond single crystals grown in a Fe-Ti-B-C system

Boron-doped diamond (BDD) single crystals were synthesized using a large-volume cubic high-pressure apparatus (SPD-6 × 1200) in the Fe-Ti-B-C system under conditions of 6.0 GPa and temperatures ranging from 1410 to 1435 °C. Scanning electron microscope (SEM) images revealed linear textures, cracks, and dendritic growth texture on the crystal surface. The Raman spectrum exhibited additional bands at approximately 480, and 1220 cm−1, indicating high levels of boron doping. X-ray photoelectron spectroscopy (XPS) measurements confirmed the presence of boron on the crystal surface, bonded as BC and BO. By utilizing the Hall effect, the highest recorded carrier concentration in the crystal was determined to be 1.17 × 1019 cm−3, a relatively high level for diamond single crystals synthesized via the high pressure and high temperature (HPHT) method. Moreover, thermogravimetric analysis (TG) measurements verified that boron doping enhanced the thermal stability of the diamond.