INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
Optical Properties in Mechanically Alloyed ZnO-Based Ternary Oxides
L. C. DAMONTE; F.J.MANJON; B.MARÍ
Conferencia; E-MRS Fall Meeting 2007; 2007
Cation substitution modifies the band width of ZnO leading in consequence to a change in optical and electronic properties for its potential use in many demanding technological applications. Mechanical milling has proved to be an effective and simple technique to produce nanocrystalline powders and the possibility of obtain large quantities of materials. In this work we present a structural and optical characterization of M-alloyed ZnO (M: Mg and Cd) powders obtained by mechanical milling. The starting materials were commercially ZnO, MgO and CdO powders. Zn1-xMxO samples with different concentrations of M-element (x between 5-30%) were prepared by mechanical milling in a vibratory horizontal ball mill. In a previous work  we analyzed the evolution with milling time of cation substitution by X-ray diffraction and positron annihilation spectroscopy. As milling proceeds an unambiguous reduction of grain size and homogenization are observed. It is the aim of this work the Raman and optical characterization of the ternary alloys. The energy position of the fundamental absorption edge shifts to UV or IR depending of the guest element. From the analysis of Raman spectra the incorporation of the M-element in the ZnO lattice can be followed. The lattice disorder introduced by the mechanical work is also evidenced in the Raman features.  Composition influence on positron annihilation parameters in ZnO-based nanocrystal semiconductor powders, L.C. Damonte, M.A. Hernández Fenollosa, V. Donderis and B. Marí, Physica (C) (2007) in press.