Defect-related photoluminescence of hexagonal boron nitride

Physical review. B, Condensed matter (Impact Factor: 3.66). 11/2008; DOI: 10.1103/PhysRevB.78.155204
Source: arXiv

ABSTRACT Photoluminescence of polycrystalline hexagonal boron nitride (hBN) was measured by means of time- and energy-resolved spectroscopy methods. The observed bands are related to DAP transitions, impurities and structural defects. The excitation of samples by high-energy photons above 5.4 eV enables a phenomenon of photostimulated luminescence (PSL), which is due to distantly trapped CB electrons and VB holes. These trapped charges are metastable and their reexcitation with low-energy photons results in anti-Stockes photoluminescence. The comparison of photoluminescence excitation spectra and PSL excitation spectra allows band analysis that supports the hypothesis of Frenkel-like exciton in hBN with a large binding energy.

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    ABSTRACT: The BN and BCNO phosphors were prepared at 750°C using different methods and their structure and luminescent properties were investigated. All the prepared samples were turbostratic boron nitride structure. The SEM and high-resolution TEM images show that the BCNO phosphors are polycrystalline in nature and include some nanocrystals. The carbon and oxygen impurities have great effects on the excitation, emission, and absorption spectra of BN and BCNO phosphors. The first-principle calculations results indicate that the carbon and oxygen impurities will produce energy levels in the band gap, which can affect the spectra properties of BCNO phosphors. The spectra properties of BN and BCNO phosphors can be well explained by a simplified energy level diagram.
    Journal of the American Ceramic Society 01/2014; 97(1). · 2.43 Impact Factor
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    ABSTRACT: Boron nitride is a promising material for nanotechnology applications due to its two-dimensional graphene-like, insulating, and highly-resistant structure. Recently it has received a lot of attention as a substrate to grow and isolate graphene as well as for its intrinsic UV lasing response. Similar to carbon, one-dimensional boron nitride nanotubes (BNNTs) have been theoretically predicted and later synthesised. Here we use first principles simulations to unambiguously demonstrate that i) BN nanotubes inherit the highly efficient UV luminescence of hexagonal BN; ii) the application of an external perpendicular field closes the electronic gap keeping the UV lasing with lower yield; iii) defects in BNNTS are responsible for tunable light emission from the UV to the visible controlled by a transverse electric field (TEF). Our present findings pave the road towards optoelectronic applications of BN-nanotube-based devices that are simple to implement because they do not require any special doping or complex growth.
    Scientific Reports 09/2013; 3:2698. · 5.08 Impact Factor
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    ABSTRACT: Hexagonal boron nitride (hBN) thin films were deposited on silicon and quartz substrates using sequential exposures of triethylboron and N2/H2 plasma in a hollow-cathode plasma-assisted atomic layer deposition reactor at low temperatures (≤450°C). A non-saturating film deposition rate was observed for substrate temperatures above 250°C. BN films were characterized for their chemical composition, crystallinity, surface morphology, and optical properties. X-ray photoelectron spectroscopy (XPS) depicted the peaks of boron, nitrogen, carbon, and oxygen at the film surface. B 1s and N 1s high-resolution XPS spectra confirmed the presence of BN with peaks located at 190.8 and 398.3 eV, respectively. As deposited films were polycrystalline, single-phase hBN irrespective of the deposition temperature. Absorption spectra exhibited an optical band edge at ~5.25 eV and an optical transmittance greater than 90% in the visible region of the spectrum. Refractive index of the hBN film deposited at 450°C was 1.60 at 550 nm, which increased to 1.64 after postdeposition annealing at 800°C for 30 min. These results represent the first demonstration of hBN deposition using low-temperature hollow-cathode plasma-assisted sequential deposition technique.
    Journal of the American Ceramic Society 09/2014; · 2.43 Impact Factor

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