VUV spectroscopy and electronic excitations in nano-size alumina

Abstract

a b s t r a c tLuminescence properties and electronic excitations of d-and Q-phases of Al 2 O 3 nano-powders, prepared by plasma processing technique, were studied using time-resolved luminescence spectroscopy under vacuum ultraviolet excitation. The fundamental absorption edge was found at 7.5 eV, which is 1.5 eV less than that of a-Al 2 O 3 in agreement with theoretical predictions for transition alumina. The broad-band emissions with maxima at 5.5 and 4.6 eV are assigned to radiative decay of the intrinsic excitations. Emission of transition metal impurities was found near 1.75 eV. The emission bands peaked at 3.1 and 2.6 eV are assigned to F þ and F centres, respectively.

Intrinsic and defect related luminescence in double oxide films of Al–Hf–O system under soft X-ray and VUV excitation

“…Thus, the photons with energy of 130 eV were almost completely absorbed in these films providing maximum excitation efficiency. The PL spectra of these phases in Al 2 O 3 had been studied previously [28,29].…”

Interface behavior of Al2O3/Ti joints produced by liquid state bonding

“…Any degradation of mechanical and/or electrical properties of these ceramic materials might seriously cause malfunction of the systems and shorten their life expectancy. On the other hand, Kirm et al (2010) studied luminescence properties and electronic excitation of δ-and Θ-phases of Al 2 O 3 nano-powders using time-resolved luminescence spectroscopy under vacuum ultraviolet excitation, and Zvonarev et al (2015) studied the effect of structural changes on luminescent and dosimetric properties through variations of the particle size and porosity of alumina ceramics synthesized by annealing compacted nanopowders, showing that formation of fine grains and the growth of their fraction with the increasing annealing temperature increases the thermoluminescence intensity and expands the usable dose range upwards.…”

Computer simulation of the photoluminescence of nanostructured aluminum oxide excited with pulsed synchrotron radiation

“…It is well known that many properties of corundum under study are determined by the concentration of F centers (oxygen vacancies with two captured elec trons) and F + centers (oxygen vacancies with one cap tured electron) [4]. The maximum of the optical absorption band for F centers is located at 6.1 eV, which causes difficulties upon the excitation of these centers with ultraviolet radiation in the atmosphere.…”

“…A series of papers [4,5] is dedicated to studying corun dum containing anion vacancies with the use of SR for its excitation (including time resolved studies). The authors of these papers obtained new results on the excitation transport and the specificity of intracenter transitions and presented proof of the existence of excitons related to defects and of their participation in PL processes [6,7].…”