Synthesis, conductivity and high-pressure phase transition of amorphous boron carbon nitride

Amorphous BCN was prepared by chemical solid-state reaction between boracic acid (H 3BO 3) and melamine (C 3N 6H 6) in mass ratios of H 3BO 3 to C 3N 6H 6 of 1:2–1:4 and heat treatment at 1273 K under 10 −3 Pa. The amorphous B C N behave insulating property below 890 K, but semiconductor conductivity above 890 K and show different conductivity–temperature relationships in temperature ranges of 913–963 and 963–1083 K. The conductive activation energy was calculated to be 0.26–0.34 eV at 913–963 K and 1.02–1.10 eV at 963–1083 K, implying that the conduction mechanisms are different in the different temperature ranges. Annealed for 40 min at 1473 K under 4.0 GPa, the amorphous BCN with the chemical composition B 0.48C 0.29N 0.23 was prepared in the mass ratio of 1:3 crystallizes into single-phase hexagonal (h-BCN) compound with lattice constants of a=0.2506 nm and c=0.6652 nm. Raman scattering peaks were observed at 1330, 1364,1584 and 1617 cm −1 in the Raman spectrum (RS) of h-BCN, of which the peaks located at 1330 and 1617 cm −1 are assigned to characteristic peaks of the h-BCN.