Fotoluminiscences procesi dažādi strukturētā Al2O3

Abstract

Darbā ir pētītas alumīnija oksīda nanopulveru spektrālās īpašības. Tika iegūti fotoluminiscences un ierosināšanas spektri gan pie istabas, gan pie zemas temperatūras. Ar iegūto fotoluminiscences un ierosmes spektru palīdzību tika analizēi procesi, kurus rada ultravioletā gaisma Al2O3 paraugos. Tika noskaidrots, ka nomināli tīra alumīnija oksīda nanopulveru fotoluminiscenci nosaka nekontrolējamo piejaukumu centru Fe3+, Mn4+ un Cr3+ klātbūtne. Saistot paraugu fāzu struktūru ar to spektrālām īpašībām, secinājām, ka platā luminiscences josla ar maksimumu 750 nm rodas paraugos ar δ fāzi, bet šauro luminiscences joslu parādīšanās 670 – 720 nm rajonā saistās ar α fāzes rašanos. Savukārt fāzes pāreja alumīnija oksīda nanopulveros izraisa aktīvā luminiscences centra maiņu: δ fāzē luminiscē Fe3+ jons, bet α fāzē luminiscē Mn4+ un Cr3+ joni. Darba rezultāti tika prezentēti divās zinātniskajās konferencēs.

In this work spectral properties of aluminum oxide have been studied. Photoluminiscence and photoluminiscence excitation spectra were obtained at both room and low temperatures. With spectra obtained it is possible to study processes, which were caused by UV light in Al2O3. It was found that photoluminiscence of aluminum oxide was caused by presence of Fe3+ , Mn4+ and Cr3+ impurity centers. Analysing correlation between phase structure and spectral characteristics of alumina nanopowders it was found that the broad luminiscence band with maximum at 750 mn is produced in samples with δ phase, but the appearance of the fine band group in 760 – 720 nm range is associated with generation of α phase. Phase transition switches the active luminiscence centers: Fe3+ emits in δ phase, Mn4+ and Cr3+ emit at α phase. Results received in this work were presented at two scientific conferences.