Высокотемпературная диффузия акцепторной примеси Ве в AlN

The high-temperature diffusion of an acceptor impurity of beryllium (Be) into bulk single-crystal aluminum nitride (AlN) has been studied. It is shown that the introduction of Be leads to the appearance of green luminescence of AlN, which is stable at room temperature and is observed over the entire thickness of the sample. It was shown by the method of luminescence analysis that the Be diffusion process is most efficiently realized in the temperature range from 1800°C to 2100°C and is characterized by extremely high diffusion coefficients D = 10-7 cm2/s and 10-6 cm2/s, respectively. It is shown that a prolonged diffusion process (t ≥ 1 hour) at a temperature of 2100°C leads to concentration quenching of the luminescence of near-surface AlN layers with a thickness of ≈ 80 μm, which makes it possible to estimate the concentration of beryllium impurities in the near-surface layer on the order of 10E19 cm-3.

The Influence of Recrystallization on Zinc Oxide Microstructures Synthesized with Sol–Gel Method on Scintillating Properties

Zinc oxide (ZnO) is one of the wide-bandgap semiconductors, which may be useful in a plethora of electronic, optical, piezoelectric, and scintillating applications. The following article consists in a structural and luminescence analysis of ZnO microfilms grown on a sapphire substrate with a sol–gel method. The films were annealed at different temperatures. The structures were investigated with the XRD and Raman methods, by which the influence of the substrate on the structure of the film was determined. The luminescence of films was investigated with room-temperature fluorescence, radioluminescence, and thermoluminescence.

Identifying Heated Rocks Through Feldspar Luminescence Analysis (pIRIR290) and a Critical Evaluation of Macroscopic Assessment

Throughout (pre)history, non-flint rocks have been used to structure fireplaces, to retain heat, to boil liquids, and to cook food. Thus far, the identification of heated non-flint rocks in archaeological contexts largely depends on a visual (macroscopic) assessment using criteria thought to be diagnostic for thermal alteration. However, visual identification can be subject to observer bias, and some heat-induced traces can be quite difficult to distinguish from other types of weathering or discolouration. In this paper, we present feldspar luminescence analysis as an independent, objective way to identify heated non-flint rocks and to evaluate the results against the established visual macroscopic method for the identification of such pieces. This is done by submitting manuported rocks with and without inferred macroscopic characteristics of heating, originating from the Last Interglacial, Middle Palaeolithic site Neumark-Nord 2/2 (Germany), to feldspar luminescence analysis (pIRIR290). Results of the feldspar luminescence analysis are compared with the visual assessments. This proof of concept study demonstrates the potential of luminescence analyses as an independent, quantitative method for the identification of heated rocks—and their prehistoric applications like hot-stone cooking, specifically for cases where macroscopic assessment cannot provide reliable determinations.

Прямые оптические методы исследования в аналитике фенола

The study investigates the applicability of direct optical methods to measure phenol in water without the use of “wet chemistry” and concentration techniques. The detection limits are estimated for determining phenol concentration from absorption spectra and luminescence. Inelastic scattering (Raman effect) of the solvent is proposed as the mechanism that limits the use of direct luminescence analysis to measure phenol concentrations; the scattering becomes comparable to the luminescent signal at phenol concentration near 10 μg l-1, even though the sensitivity of the method is high enough to detect concentrations that are 50 times lower