Comparative Study of Thermodynamic Properties of Metallic and Semiconducting Nanoparticles in Dielectric Matrix

Abstract

AbstractThe mechanism of growth as well as optical and microstructural data dealing with the process of melting of metallic (Pb, Sn) and semiconducting (Ge) particles in dielectric matrix are reported and discussed. Details are given on the growth of such systems based on a self organization method that allows a rather regular shape of the particles (truncated spheres) relative low size dispersion (≤ 20%), wide range of particle size variation and negligible effects due to stress or contamination. The features of these growth techniques allow a careful study of the melting behavior vs. size that has been investigated using optical reflectivity methods and transmission electron microscopy techniques. These experimental results have made possible a careful investigation on the thermodynamics of these systems and the deduction of interesting data concerning: a) conditions for the existence of surface melting and decrease of melting temperature; b) interfacial effects related to shape and curvature of the particles; c) onset of rotations and phase fluctuations in connection with surface melting.