Synthesis And Characterization Of P, N And H Synergistic Doped Diamond Crystals Under High Pressure And High Temperature

Nitrogen is one of the most common impurities in diamond. Nitrogen exists in thelattice as a single substitution atom (C center) in the synthetic diamond of Ib type，thenitrogen content is generally about300ppm; While most natural diamond is Ia type andthe nitrogen is present in the form of condensed matter (A center or B center) with anitrogen content of about3000ppm. The comparison of synthetic diamond with naturaldiamond shows that there are great differences between them not only in the terms ofnitrogen content but also in the presence of nitrogen atoms in the diamond. Thereforestudying the synthetic of gem diamonds with high nitrogen content and changing thepresence of nitrogen atoms in the crystal have far-reaching significance for exploring theformation mechanism of natural diamond. At present the adjunction of nitride in thesynthesis chamber is the main way to improve the nitrogen content in the study ofdiamond with high nitrogen content. Moreover, the nitride will bring in other impuritieselement which will improve the types of impurities in the synthesis crystal and meanwhilethe other impurities will affect the entry of Nitrogen into the diamond and the presence ofthe Nitrogen in the lattice.Therefore, in this article, we synthesize high nitrogen singlecrystal diamond by adding carbonyl iron powder. Its influence on high temperature andhigh pressure synthesis of diamond has attracted people’s interests. As we known,hydrogen is the lightest element in the periodic table, it will have great impact on someproperties of diamond. Especially, it will have great impact on electrical properties ofhydrogen and other impurity elements co-doped diamond crystals. Therefore, this articlefocuses on synthesis of P, N and H synergistic doped diamond crystals was investigated.Our works are divided into following sections:Firstly, we investigates the relation among the internal temperature of the cavity tothe extension of synthesis time; Analyzed some phenomena occurring in the diamondsynthetic process. Focuses on the large seed crystal and its smoothness influence ondiamond growth rate and quality.Second, we report on the influence of carbonyl iron powder impurity in metal meltson the growth process, morphology, and defect-and-impurity structure of diamondcrystals. We studied the properties of the crystals by OM, ESM, FTIR and Raman spectrum. By optical microscope to investigate the synthesis of diamond crystal colorchange; FTIR spectrum shows the nitrogen concentration and the form of nitrogen atom.With SEM looked at the diamond two-dimensional on crystal growth.Third, on basis of nitrogen and hydrogen co-doped diamond crystals, We study theoptimization effect of hydrogen on the crystal quality. FTIR spectrum shows the nitrogenconcentration and the form of nitrogen atom.Fourth, a series of nitrogen and hydrogen-doped diamond crystals is successfullysynthesized using P3N5as the nitrogen source in a catalyst-carbon system. The syntheticcrystals has the A form with C form composite. The3107cm-1peak is observed in theinfrared absorption spectra of all types of Ia diamonds, but it has not been observed in theiron-based catalyst.