Boron Carbonitride Films with Tunable Composition: LPCVD and PECVD Synthesis Using Trimethylamine Borane and Nitrogen Mixture and Characterization

Abstract

This study reports the chemical vapor deposition of amorphous boron carbonitride films on Si(100) and SiO2 substrates using a trimethylamine borane and nitrogen mixture. BCxNy films with different compositions were produced via variations in substrate temperature and type of gas-phase activation. The low-pressure chemical vapor deposition (LPCVD) and plasma-enhanced chemical vapor deposition (PECVD) methods were used. The “elemental composition—chemical bonding state—properties” relationship of synthesized BCxNy was systematically studied. The hydrophilicity, mechanical, and optical properties of the films are discussed in detail. The composition of films deposited by the LPCVD method at temperatures ranging from 673 to 973 K was close to that of boron carbide with a low nitrogen content (BCxNy). The refractive index of these films changed in the range from 2.43 to 2.56 and increased with temperature. The transparency of these films achieved 85%. LPCVD films were hydrophilic and the water contact angles varied between 53 and 63°; the surface free energy was 42–48 mN/m. The microhardness, Young’s modulus and elastic recovery of LPCVD films ranged within 24–28 GPa, 220–247 GPa, and 70–74%, respectively. The structure of the PECVD films was close to that of hexagonal boron nitride, and their composition can be described by the BCxNyOz:H formula. In case of the PECVD process, the smooth films were only produced at low deposition temperatures (373–523 K). The refractive index of these films ranged from 1.51 to 1.67. The transparency of these films achieved 95%; the optical band gap was evaluated as 4.92–5.28 eV. Unlike LPCVD films, they were very soft, and their microhardness, Young’s modulus and elastic recovery were 0.8–1.4 GPa, 25–26 GPa, and 19–28%, respectively. A set of optimized process parameters to fabricate LPCVD BCxNy films with improved mechanical and PECVD films with high transparency is suggested.

(B, N)‐Rich B−C−N Nanosheet‐assembled Microwires as Effective Electrocatalysts for Oxygen Reduction Reaction

“…For N 1s peaks (Figure 3d), which can also be divided into two peaks corresponding to NÀ B (397.7 eV) and NÀ C (398.3 eV). [14,16] The B: C: N atomic ratio calculated from the XPS spectra is about 6.5: 1: 5.8.…”

“…Theoretical calculations also have revealed that the electronic and optical properties of ternary BÀ CÀ N nanostructures can be tailored by changing its composition, which show great potential applications in optoelectronics device, supercapacitors, and catalyst. [8] Several methods have been reported for the synthesis one-dimensional (1D) BÀ CÀ N nanotubes (BÀ CÀ NNTs) and 2D BÀ CÀ N nanosheets (BÀ CÀ NNSs), [9][10][11][12][13][14][15][16][17][18] However, B doping and N doping have a very low efficiency by boric acid and N-containing compounds due to their poor reactivity. Thus, the BÀ CÀ N micro-nano structures with regular morphology prepared by these methods either suffer from low yield and/or low purity, which would greatly limit the application of BÀ CÀ N nanomaterials.…”