Cathodoluminescence of Al doped ZnO nanopowders
|Larisa Grigorjeva 3, Donats Millers 3, Robert R. Piticescu 1, Tomasz Strachowski 4, Krisjanis Smits 3, Witold Łojkowski 4, Claude J. Monty 2|
1. Institute for Non-ferrous and Rare Metals, 102 Biruintei Blvd., Pantelimon 73957, Romania
ZnO powders are well known material for fluorescence displays. The luminescence band peaking at 2.5 eV one increases after firing in a reducing atmosphere. The origin of this band is not clear, but the defects such as Zn interstitial or oxygen vacancies are involved. The interstitial oxygen is one of the possible defect center responsible for the luminescence band at yellow-red region. In present investigation pulsed electron beam excitation (energy of electrons was 280 keV, pulse duration was 8 ns) was applied for cathodoluminescence spectra and luminescence decay studies on ZnO nanopowders with different Al concentration. The two types of powders were studied: obtained by hydrothemal (HY) synthesis and by vaporisation - condensation (VC) in solar reactor from the HY powders . The differences between of HY and VC powders have been studied. It is shown that along the differences obtained in SEM and TEM images (whiskers and spherical type powders) the differences in cathodoluminescence spectra were observed: VC samples show higher level of defect states luminescence and luminescence in exciton (blue) region. After VC the blue luminescence rise more than 103 times and luminescence maxima of defect band shifts from yellow (1.9 eV) to green (2.4 eV). These results confirm the change of defect type and take place the crystalline structure ordering during VC process.
The work was supported by SPUB-COST of Polish Ministry for Science and Higher Education and Project SOLFACE-LUMINANOS
Presentation: Poster at E-MRS Fall Meeting 2006, Symposium C, by Larisa Grigorjeva
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-05-17 09:48 Revised: 2009-06-07 00:44