0000000000266624
AUTHOR
Darja Jakimovica
UV-light induced luminescence processes in Al2O3 bulk and nanosize powders
Abstract UV-light induced photoluminescence (PL) and thermoluminescence (TL) have been studied in the alumina (Al2O3) bulk and nanosize powders. It has been found that luminescence properties of the studied alumina powders are determined mainly by presence of the uncontrolled impurities of titanium, iron and chromium. Despite the general similarity of PL characterized by two main emission band around 400 and 750 nm a number of differences has been observed in relative yield and position of the emission bands as well as in the excitation spectrum of the short wavelength band. Essential differences have been observed also in the intensity of the TL signal, TL curves and TL emission spectra re…
Peculiarities of photoluminescence of Al2O3 bulk and nanosize powders at low temperatures
Abstract Photoluminescence has been studied in the aluminum oxide (Al2O3) bulk and nanosize powders in the 300–8 K temperature range. In both samples luminescence spectrum is characterized by presence of broad blue and red bands caused mainly by emission from the uncontrolled titanium impurity. At low temperatures luminescence intensity increases by several times and the red band obtains fine structure. The nature of the fine structure is discussed suggesting manifestation of splitting of the Ti3+ emitting level due to Jahn–Teller effect or overlapping of Ti3+ emission band with narrow lines from other emitting ions. The observed differences in low-temperature spectral features of nanopowde…
Spectral characterization of bulk and nanostructured aluminum nitride
Spectral characteristics including photoluminescence (PL) spectra and its excitation spectra for different AlN materials (AlN ceramics, macro size powder and nanostructured forms such as nanopowder, nanorods and nanotips) were investigated at room temperature. Besides the well known UV-blue (around 400 nm) and red (600 nm) luminescence, the 480 nm band was also observed as an asymmetric long-wavelength shoulder of the UV-blue PL band. This band can be related to the luminescence of some kind of surface defects, probably also including the oxygen-related defects. The mechanisms of recombination luminescence and excitation of the UV-blue luminescence caused by the oxygen-related defects were …