Grow Large High-Quality Diamonds with Different Seed Surfaces

Large high-quality type Ib diamond crystals have been grown with different seed surfaces by temperature gradient method at 5.5GPa, 1500--1600K, with NiMnCo alloy as the metal solvent. Compared with 100 as the growth surface, the growth region of large high-quality diamond crystals with 111 as the growth surface at a higher growth rate shifts markedly from lower temperatures (suitable for 100-facet growth) to higher temperatures (suitable for 111-facet growth). However, regardless of different growth surfaces, 100 or 111, the grown crystals of sheet-shaped shape are most difficult for metal inclusions to be trapped into, and whether or not matched growth between the seed surfaces and the growth temperatures determines the crystal shapes. In view of the growth rates, large high-quality diamond crystals of sheet-shaped shapes can be grown at a growth rate of above 2.5mg/h, while the growth rate of large high-quality diamond c