Synthesis and characterization of diamond with KBH4 additive under high pressure and high temperature conditions

Abstract

In this paper, diamond single crystals have been successfully synthesized with potassium berohydride (KBH4) additive from 0 wt.% to 0.4 wt.% in the NiMnCo–C system at 6 GPa and temperature range of 1300[Formula: see text]C–1350[Formula: see text]C by temperature gradient growth (TGG) method. The results of experiments showed that the color of diamond crystals changed from light yellow to dark blue to black, as the KBH4 content increases from 0 wt.% to 0.4 wt.%. The results of FTIR absorption spectroscopy showed that the peaks of boron-related enhanced with an increase of KBH4 additive. The XPS results showed that the boron, hydrogen, nitrogen and oxygen coexisted in the diamond crystal. The results of Hall effect measurements indicated that the synthesized diamonds using KBH4 as additive presented [Formula: see text]-type semiconductor characterizations. The Hall mobility was nearly equivalent between diamond crystals of with 0.2 wt.% and 0.4 wt.% KBH4 additive, but which was all extremely low due to scattering causing by N and O defects. While the concentrations of carrier and conductivity of the co-doped diamonds enhanced with increasing KBH4 additive.