Microstructure, Properties And Mechanism Of Boron-Doped Diamond Single Crystal

The boron-doped diamond, so-called â…¡b type diamond, processes many wonderful properties such as oxidation-resistance, impact-resistance, stable chemical character and excellent semiconductor performance. So it shows exciting application in many industry fields, and especially in the electronic field. Although a large number of diamond single crystals are produced every year, the homemade diamond is mainly low-valent and the quality can not compare with that of diamond produced by several monopolized companies, such as G.E., DeBeers and Winter. Therefore it is of great significance to synthesize and investigate the excellent boron-doped diamond single crystal.In the present paper, boron-undoped diamond and boron-doped diamonds were synthesized by using different boron-doped Fe-based alloy catalysts with different composition produced by powder metallurgy. The morphology and structure of the undoped diamond, boron-doped diamond and metallic film surrounding diamond were studied by means of diamond shape measurement system (Diashape), Scanning electron microscope (SEM), Atom force microscope (AFM), Transmission electron microscope (TEM), Raman spectrum (Raman), Infrared ray (IR), X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM). Meanwhile the character performances of the two kinds of diamonds were measured by static strength measurement, (thermal) impact toughness measurement, different thermal analysis (DTA) and homemade resistance-temperature measurement system. The nucleation and growth mechanism of the diamond were discussed according to the experimental results and carbide-diamond interface electron structures calculated via Empirical Electron theory (EET) and Thomas-Fermi-Dirac-Cheng (TFDC).The boron-doped diamonds are gray or even opaque black dependent on the boron concentration in diamond and their crystal shape is mainly...