Search results for "Aluminium nitride"
showing 5 items of 5 documents
Aluminium nitrate ceramics: a potential UV dosemeter material.
2002
The ceramic material AlN-Y 2 O 3 is proposed as a potential ultraviolet radiation (UVR) dosemeter using optically stimulated luminescence (OSL) and thermally stimulated luminescence (TL). Experimental studies have shown that AlN ceramics exhibit attractive characteristics suitable for practical UV dosimetry applications. The features are: (1) the spectral sensitivity covers the 200-350 nm range, in the UV-B region it is similar to that of human skin; (2) the angular dependence of the incident radiation follows the cosine law; (3) high yields of both UVR-induced OSL and TL signals compared to those of Al 2 O 3 :C; and (4) a large dynamic range TL signal (5 orders of magnitude). Although ther…
Theoretical simulations of regular and defective aluminium nitride nanotubes
2007
For theoretical simulation on AlN nanotubes (NTs) of different chiralities (armchair-and zigzag-type) and uniform diameters, we have considered their single-walled (SW) 1D periodic models. For this aim, we have performed ab initio DFT calculations on AlN SW NTs using formalism of the localized Gaussian-type atomic functions as implemented in CRYSTAL-03 computer code. We have shown that the smaller the diameter of AlN single-walled nanotube is, the closer its electronic and structural properties to AlN bulk. We have analysed an influence of N vacancies (neutral F centres) created by either soft irradiation of nanotubes or under experimental conditions of their growth, on the atomic and elect…
Luminescence, vibrational and XANES studies of AlN nanomaterials
2007
Abstract The paper reports comparative studies on synthesized aluminium nitride nanotubes, nanoparticles and commercially available micron-sized AlN powder using different spectroscopic techniques: cathodoluminescence measurements (CL), X-ray absorption near edge spectroscopy (XANES) and Fourier-transform infrared spectroscopy (FTIR). Crucial distinctions in CL spectra are observed for nano- and microsized aluminium nitride powders; systematic shift of the IR absorption maximum has been detected for nanostructured aluminium nitride as compared to commercial samples. Through XANES experiments on Al K-edge structural differences between nano- and bulk AlN are revealed, intensity of features i…
Luminescence processes induced by UV radiation in A1N nanotips and nanorods
2008
Abstract The processes of the UV radiation induced photoluminescence, thermoluminescence and optically stimulated luminescence in the AlN nanotips and nanorods are studied in comparison with those in the AlN ceramics. The emission spectra of the UV radiation induced luminescence processes in the AlN nanostructures are similar to those of AlN ceramics, presumably originating from recombination processes with participation of the oxygen-related centres. In the nanostructures the luminescence processes occur mainly through the excitation of the host lattice, probably due to the smaller content of the randomly distributed defects in the lattice. The observed small mutual differences in the lumi…
UV light induced processes in pure and doped AlN ceramics
2021
The present research has been sponsored by the Latvian Council of Science , Grant No. lzp-2018/1-0361 “Research of luminescence mechanisms and dosimeter properties in prospective nitrides and oxides using TL and OSL methods “; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 73950 , project CAMART 2