The structure and luminescence of boron nitride doped with Ce ions

Highly luminescent boron nitride (BN) was synthesized by pyrolysis of molecular adduct prepared by chemical mixing of boric acid and melamine with a small amount of cerium nitrate. After pyrolysis, Ce ions were substitutionally incorporated to B3N3 hexagonal layer of turbostratic BN at a very low doping level which was estimated to be less than 7 × 1018 atoms/cm3. Ordered stacking of hexagonal layers along c-axis of BN or transformation of turbostratic BN to hexagonal BN was induced by addition of Ce ions even though the amount of Ce ions surpassed substitutional doping limits. The intense photoluminescence (PL) spectrum of Ce-doped BN was detected at 390 nm by excitation of UV light (λ = 314 nm) and PL intensity was improved with increasing level of Ce addition following the enhanced crystallinity of turbostratic BN. The origin of UV-emission was ascribed to the transition from the crystal field components of the 5d level to the 4f ground states of the Ce3+ ion.