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

Amorphous BCN was prepared by chemical solid-state reaction between boracic acid (H3BO3) and melamine (C3N6H6) in mass ratios of H3BO3 to C3N6H6 of 1:2-1:4 and heat treatment at 1273 K under 10−3 Pa. The amorphous BCN 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 B0.48C0.29N0.23 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.