We have studied the bonding states of BC2N thin films prepared by chemical vapor deposition, one of the new layered BCN compounds. The chemical bonding states of boron, carbon, and nitrogen atoms in the BC2N thin films were investigated by using x-ray photoelectron spectroscopy to measure chemical shifts of 1s electrons, being compared with those in graphite and hexagonal (h-) BN. The results exhibited that the thin films had significant B–C and C–N bonds and were clearly different from graphite and h-BN, indicating that an atomic-level hybrid of the three elements was synthesized.

The electrical properties of BC2N thin films have been investigated in terms of the temperature dependence of the resistivity and Hall effect measurements. The BC2N thin films were prepared by chemical vapor deposition from acetonitrile and boron trichloride on polycrystalline Ni and quartz substrates. The experimental results indicated that the BC2N films were p-type semiconductors on both substrates, with acceptor levels between 7.5 and 23 meV relative to the valence band. The hole mobility on Ni substrates was one order of magnitude higher than that on the quartz substrates, suggesting that the thin film quality is better on Ni substrates than on quartz substrates.

The dependence of crystalline orientation in Y-Ba-Cu-O films on oxygen partial pressure and substrate temperature has been investigated for films prepared by magnetron sputtering on (100) SrTiO3 and (100) MgO substrates. The tendencies for preferential orientation were the same on both substrates. At low oxygen pressures, the c-axis was oriented perpendicularly to the film plane. In contrast, a/c-axis oriented films were formed at intermediate oxygen pressures, and the a-axis was oriented at high oxygen pressures. At higher temperatures, c-axis oriented films were formed, even at high oxygen pressures.

The structural features of superconducting Y-Ba-Cu-O films prepared by reactive sputtering have been discussed in relation to the preparation conditions. Conductivity anisotropy and the anomalous diamagnetic response observed for the films have also been discussed.

No abstract