B/C/N系グラファイト様層状化合物薄膜の成長に及ぼす単結晶基板の影響

摘要

Thin films of B/C/N materials were prepared on Ni (111), Ni (100), Ni (110) and Pd (111) single crystal substrates by low pressure chemical vapor deposition (LPCVD) using acrylonitrile and boron trichloride as starting materials at a temperature of 1120K. The films prepared on Ni (100) and Ni (110) substrates were polycrystalline with compositions in a range of B_(1.8~2.2)C_(1.0)N_(1.8 approx 2.4), while the film prepared on Ni (111) was a single crystal with larger B and N contents (B_(4.6)C_(1.0)N_(4.8)). These results were explained by the following reason. The films were prepared on Ni (100) and Ni (110) only by catalytic role of Ni, while a heteroepitaxial growth was made on Ni (111) whose nearest neighbor Ni-Ni distance is close to the lattice constant of h-BN. The film prepared on Pd (111) whose nearest neighbored atomic distance is larger than that of graphite by 12 percent was polycrystalline carbon with turbostratic structure. In this case, significant difference in catalytic effect between Ni and Pd could cause the change in composition of the films. These results suggest that the catalytic effect is one of the most important factors for the preparation of B/C/N thin films with high crystallinity. Moreover, the consistency of lattice constant between substrate and the growing film should be essential in order to obtain a single crystal B/C/N thin film.