Influence of carbon convection field on high quality large single crystal diamonds morphology under high pressure and high temperature

Abstract

The temperature and convection fields of a catalyst with three different heights were simulated in a temperature gradient growth (TGG) system under high pressure and high temperature (HPHT) conditions. Temperature fields were simulated to rule out the influence of temperature on the crystal morphology. The features of the calculated convection field could predict the particular situations of diamond growth systems very well, and could explain the change of diamond morphology accompanying the growth process. According to the calculated results, we predict that the morphology of a diamond crystal changes from cubic crystal to cub-octahedral. A good agreement has been obtained between the calculated results and the observed experimental data. The morphology and structural properties of the synthesized samples are characterized by optical microscopy and a Raman spectrum. The results illustrate that the synthesized diamond crystals have less lattice distortion and with high quality.