Synthesis of large diamond single crystals under high pressure and high temperature through effective utilization of the synthesis cavity

Abstract

To make maximal use of the synthesis cavity and improve the production efficiency, we designed the double seed bed method to synthesize large diamond crystals under high pressure and high temperature (HPHT) conditions, and the results were both theoretically calculated and verified by experiments. The theoretical and experimental results were compared with those of the traditional single seed bed method. Furthermore, the obtained diamond crystals were characterized by Raman spectroscopy and Fourier infrared spectroscopy (FTIR). The designed method can shed light on the commercial production of synthetic diamonds. Additionally, the surface defects formed during the crystal growth process were noticed, and the formation mechanism of the {100}-oriented surface defects was discussed.