Thermally stimulated processes in the luminescence of carbon-related defects for h-BN micropowder
| Autor: | Alexander Vokhmintsev, S.A. Shalyakin, M.G. Minin, Ilya Weinstein |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Radiation Photoluminescence Materials science Quenching (fluorescence) Analytical chemistry Activation energy Atmospheric temperature range Kinetic energy 01 natural sciences 030218 nuclear medicine & medical imaging Brillouin zone 03 medical and health sciences 0302 clinical medicine 0103 physical sciences Luminescence Instrumentation Excitation |
| Zdroj: | Radiation Measurements. 124:35-39 |
| ISSN: | 1350-4487 |
| DOI: | 10.1016/j.radmeas.2019.03.001 |
| Popis: | With band-to-band (5.9 eV) excitation of a micropowder of hexagonal boron nitride with a content of carbon and oxygen impurities of ≤3.5 at. %, the peculiarities of the luminescence at 3.76 eV (330 nm) in the temperature range of 300–873 K have been studied. For thermally activated processes responsible for peaks at 331, 353 and 597 K in the spectral band, the kinetic parameters such as activation energy, the effective frequency factor, and kinetics order have been estimated. For this, curve fitting, the initial rise and “EA - Tstop” methods as thermally stimulated luminescence (TSL) techniques have been utilized. Analysis of the experimental temperature dependencies of the photoluminescence (PL) intensity has been carried out within the framework of the Mott relation with two independent quenching channels and taking the TSL contribution observed into account. The processes of PL temperature quenching have been shown to proceed by an external mechanism and to be characterized by energies of EQ = 1.43 and 1.39 eV. It has been concluded that the calculated values correlate with the level positions in the forbidden gap for two possible energy configurations of the CN-center for Μ- and Κ-valleys in the first Brillouin zone. |
| Databáze: | OpenAIRE |
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