TABLE OF CONTENTS This chapter provides an introduction to thermal analysis technique such as different scanning calorimeter (DSC) and differential thermal analysis (DTA) to characterize the thermal properties of nanophases and nanostructured materials. The principles introduced here should be generally applicable to all materials.
Nanophases are usually single crystals with sizes in the nanometer region (typically less than 100 nm in at least one dimension). Nanostructured materials are single or multi-phase polycrystals of which the grain sizes are in the nanometer region. Owing to this extremely small size, nanocrystals or nanostructured materials are structurally characterized by a large proportion of surface or interface atoms (ions). Since the vibrational and positional enthalpy and entropy of surface or interface atoms of nanophases and nanostructured materials evidently differ from that of atoms within the crystals, which may significantly alter a variety of physical, mechanical, and chemical properties with respect to the conventional bulk materials (Gleiter. 1988; Lu. 1996; Suryanarayana, 1995). As the nanophases, such as nanoparticles, nanowires and thin films will and have been widely applied in semiconductor industry, these differences must be identified.
The thermal property of materials is one of the most important physical properties of materials. The study of the thermal property of nanophases and nanostructured materials at present essentially concentrates on melting temperatures, thermodynamics and kinetics for nanocrystal-liquid transition and nanocrystal-glass transition, grain growth kinetics of nanophases and nanostructured materials, the specific heat of nanostructured materials, surface (interface) enthalpy. Since these thermal properties are strongly related...
