Synthesis and characterization of TiP-doped diamond in the FeNi–C system under HTHP conditions

Abstract

In this paper, phosphorus-doped diamond with n-type semiconductor properties was successfully synthesized by adding TiP to the FeNi–C system using a large-volume cubic high pressure apparatus (CHPA) at 6 GPa and 1430–1510 °C. The morphology, crystallinity, internal content, internal atomic bonding and electrical properties of the samples were studied and characterized in detail. With the increase of TiP addition, the crystal color becomes lighter, the surface defects increase, the crystal quality deteriorates, the internal stress increases, and the nitrogen content of the crystals decreases. This means that the addition of TiP not only reduces the number of nitrogen atoms entering the diamond, but also has a negative effect on the crystal quality of diamond. The addition of TiP allows phosphorus atoms to enter the diamond lattice and bond with carbon atoms, and gives the crystals n-type conductivity. The electrical conductivity is enhanced with the increase of TiP addition. TiP was used as an additive to successfully synthesize diamond with n-type semiconductor properties in the FeNi–C system. The addition of TiP not only reduces the effect of nitrogen in the system on phosphorus doping, but also has the advantages of easier access to the synthesis system and reduced impurities as a phosphide. In this paper, the possibility of TiP as a phosphorus source for the synthesis of phosphorus-doped diamond is verified, which provides valuable data for the synthesis of n-type semiconductor diamond by HPHT.