Effect of the codoping of N–H–O on the growth characteristics and defects of diamonds under high temperature and high pressure

Abstract

In this work, diamond crystals were synthesized with different doping proportions of N-H-O at 5.5-7.1GPa and 1370-1450℃. With the increase of N-H-O doping ratio, the crystal growth rate decreases, a more serve temperature and pressure condition are required for diamond nucleation process and the crystalline process for diamond are affected. [111] becomes dominant plane of diamonds, and the surface morphology is blocked, more growth texture, stacking fault and etch pit were appeared. Diamond crystals own a two-dimensional growth habit. Increasing the doping concentration also leading more nitrogen enter into diamond crystals, which is confirmed by FTIR. However, the quality of the crystal gradually deteriorates which could be ascertained by the red shift of Raman peak position and the widening of Raman full width at half maximum. With the increase of doping ratio, the photoluminescence property of diamond crystal also drastically changed. The intensity of NV center of diamond crystal changes, and several Ni-related defect center such as NE1 center and NE3 center appear. Synthesis of diamond in N-H-O bearing fluid provides important information for a deeper understanding of the growth characteristics of diamond in complex system and the formation mechanism of natural diamond as nature diamonds are almost nitrogen rich and full of various defect centers. Meanwhile, this work proves that the type of defect center in diamond crystal could be regulated by controlling the N-H-O impurities content in the synthesis system.

Diamond growth in a high temperature and high pressure Fe–Ni–C–Si system: Effect of synthesis pressure

“…Cai et al proved that regulation of the N-H-O impurity levels within the synthesis system can control the type of defect centers present in diamond crystals. [22] Sheng et al expanded Ge-V diamond applications by finding methods to improve the luminescence performance of Ge-V color centers. [23] Si-V centers in diamonds are considered as possible single-photon sources.…”