L302
Synthesis of nanocomposite thin films by pulsed laser deposition
C.N.Afonso
Inst. de Optica, CSIC
Nanocomposite materials formed by crystals with sizes of a few nanometers are excellent systems to study the nature and reactivity of interfaces down to the nanometre scale. Their special structural characteristics lead to novel magnetic, mechanical, optical or catalytic properties and thus nanocomposite materials have a great potential for a broad range of applications. Several methods have been used to produce such special materials, the control of the crystal size and size distribution being always a major issue. Pulsed laser deposition (PLD) has recently been used to produce semiconductor and oxide nanocrystals by deposition in a gas environment or metal nanocrystals by deposition both in gas and vacuum environments. This presentation will review the work reported so far under both conditions and will discuss the growth mechanisms and the influence of the deposition parameters on the structural properties of the films. In the case of metal nanocrystals embedded in an insulating host, it will be shown that the structural properties of the films produced by PLD are very good and the size distribution of the metal nanocrystals is much sharper than that reported for the nanocomposites prepared by other techniques. Finally, two examples of the special properties of these nanocomposite films will be given: i) the metal induced crystallisation of an amorphous semiconductor (Ge) in contact with Bi nanocrystals and ii) the very large third order optical non-linear susceptibility of Cu nanocrystals embedded in an amorphous Al2O3 host.
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