Orientation of B-C-N hybrid films deposited on Ni (111) and polycrystalline Ti substrates explored by X-ray absorption spectroscopy

Orientation of sp2-bonded boron carbonitride (BCN) hybrid films has been investigated. The films were synthesized on Ni (111) and polycrystalline Ti substrates by radio frequency plasma enhanced chemical vapor deposition using tris-dimethylamino borane as a single-source molecular precursor. The deposition was performed at the radiofrequency power 400-800 W at the working pressure 2.6 Pa. Formation of sp2-BCN hybrids in the samples was confirmed by X-ray diffraction (XRD). In the XRD profile, the peak at 26.3° revealed formation of crystalline phase in the samples in which the lattice planes are separated from each other by around 3.5 Å. The D band at ~ 1350 cm− 1 and the G band at ~ 1570 cm− 1 in Raman spectra also suggested presence of graphite-like sp2-B-C-N hybrid bonds. The films were composed of different B-N, B-C, and C-N bonds to form sp2-BCN atomic hybrids confirmed by X-ray photoelectron spectra. Orientation and local structures of the films were studied by near-edge X-ray absorption fine structure (NEXAFS) measurements. The dominant presence of π* and σ* resonance peaks of the sp2 hybrid orbitals in B K-edge NEXAFS spectra revealed preferred formation of sp2-BCN atomic hybrids around B atoms like-BN3 configuration in respect to the plane of Ni (111) substrate. Different orientations were suggested on the basis of polarization dependence of B K-edge and N K-edge of the NEXAFS spectra.