Photoluminescence of Hexagonal Boron Nitride (h-BN) Film

Abstract

-Hexagonal boron nitride (BN) films were prepared. The process involved, spraying BN powder-dispersed H 3 BO 4 -BCl 3 -ethyl alcohol solution on quartz plates, and the drying off quartz plates before, and annealing at 1070 °C in a nitrogen atmosphere. The optical energy band gap of the BN films was 5.28 eV. Photoluminescence peaks with energies of 3.44, 3.16, 2.97, and 2.35 eV at 10 K were observed and analyzed. Accordingly, these have resulted from donor-acceptor pair recombinations.

Cheap, Gram-Scale Fabrication of BN Nanosheets via Substitution Reaction of Graphite Powders and Their Use for Mechanical Reinforcement of Polymers

“…The two peaks at 218 nm and 228 nm represent the near band-edge emission. They are usually assigned to the intrinsic excitonic recombinations in BN materials 21 27 50 51 52 53 , corresponding to their band gap (~5.7 eV). Other three broad emission peaks are distributing from 300 nm to 500 nm, which respectively locate at 308 nm (4.03 eV), 386 nm (3.22 eV) and 442 nm (2.81 eV).…”

“…Other three broad emission peaks are distributing from 300 nm to 500 nm, which respectively locate at 308 nm (4.03 eV), 386 nm (3.22 eV) and 442 nm (2.81 eV). These three characteristic peaks may originate from B vacancies and residual C or O impurities 21 27 50 51 52 53 .…”

“…Therefore, it can be understood that the standing sheets (region 3) exhibit the highest CL intensity. For the luminescent behaviors of BN sheets at 308 nm, 386 nm and 442 nm, there is some difference from those at 218 and 228 nm because the luminescence at these wavelengths may result from B vacancies, residual C or O impurities according to the aforementioned interpretations 21 27 50 51 52 53 . It is noted that a slight variation in the defect or impurity's density should lead to a large difference of the luminescence.…”

Cathodoluminescence studies of defects in coated boron nitride

“…For the BN substrate (figure 3), two broad peaks were observed at ~2.4 eV (~516 nm) and ~3.0 eV (~416 nm). Cathodoluminescence spectral features of BN have been difficult to identify and associate with specific defect structures due to the different band gap energies (~4.5 eV to ~6.5 eV) [20] and structures associated with cubic (sp 3 -bonded) c-BN [24,25], hexagonal (sp 2 -bonded) h-BN [20,24,26], boron nitride nanotubes [24], and disordered BN such as pyrolytic pBN [24]. Broad peaks at 2.48 eV (attributed to multivacancy complexes of B and N vacancies in c-BN) and 3.12 eV (of unknown origin) have been reported in CL spectra of higher purity c-BN close to our observed peaks at ~2.4 eV and ~3.0 eV.…”