The characterization of synthetic and natural single crystal diamonds by X-ray diffraction

Natural and synthetic single crystal diamonds (types Ia, Ib, IIa and IIb) have been characterized by measurements of the X-ray integrated scattering intensity, lattice parameter and diffuse scattering. We found a drastic increase of X-ray integrated scattering intensity for natural and B-doped diamond crystals. Synthetic type IIa diamond was also measured for comparison. Measurements of the lattice parameters have been made at room temperature by using the X-ray bond method. We found that the lattice parameter is smallest for natural diamond and largest for the B-doped diamond. Diffuse scattering experiments were performed using a four circle diffractometer at room temperature. We measured the diffuse scattering for (4 0 0) Bragg reflection for the four types of crystals. The scattering intensity of the natural crystals diffuses asymmetrically to form a streak along the [1 0 0] direction parallel to the reciprocal lattice vector. These results suggest the existence of the nitrogen atom platelets on (1 0 0) plane in the natural diamond. We also found the diffuse streaks along the [1˙00] direction for (4 0 0) Bragg reflection for the B-doped crystal, suggesting that boron atoms are likely to form precipitates on the (1 0 0) plane.