1School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000 2Engineering Technology Research Center of Jiaozuo City for Advanced Functional Materials Preparation under High Pressure, Jiaozuo 454000 3Henan Joint International Research Laboratory for High Performance Metallic Material and Their Numerical Simulation, Jiaozuo 454000 4State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012
Abstract：Large diamond single crystals doped with NiS are synthesized under high pressure and high temperature. It is found that the effects on the surface and shape of the synthesized diamond crystals are gradually enhanced by increasing the NiS additive amount. It is noted that the synthesis temperature is necessarily raised to 1280$^{\circ}\!$C to realize the diamond growth when the additive amount reaches 3.5% in the synthesis system. The results of Fourier transform infrared spectroscopy (FTIR) demonstrate that S is incorporated into the diamond lattice and exists in the form of C–S bond. Based on the FTIR results, it is found that N concentration in diamond is significantly increased, which are ascribed to the NiS additive. The analysis of x-ray photoelectron spectroscopy shows that S is present in states of C–S, S–O and C–S–O bonds. The relative concentration of S compared to C continuously increases in the synthesized diamonds as the amount of additive NiS increases. Additionally, the electrical properties can be used to characterize the obtained diamond crystals and the results show that diamonds doped with NiS crystals behave as n-type semiconductors.
2019, Vol. 36 
