Thermal Properties of Indium Nanoparticles and Gold Silicide Formation by Scanning Nanocalorimetry By

This thesis is an experimental work on the thermal properties of indium nanoparticles and the interaction characteristics between gold and silicon using nanocalorimetry technique. The melting behaviors of indium thin films have been investigated. The films consist of ensembles of nanoparticles whose melting temperatures are size-dependent. We experimentally determine the relationship between a nanoparticle’s radius and its melting point by combining the caloric results with nanoparticle size distributions from TEM. The results show a linear melting point depression. Moreover, we found the discrete nature of nanoparticles during the early stage of thin film growth ⎯ the measured heat capacity values show several maxima at certain temperatures which suggest preferred states exist among supported nanoparticles. These maxima are related to each other by increments of one monolayer of indium atoms which can be extended from the magic numbers observed previously in cluster beams. For the first time, the nanocalorimetry is utilized to characterize thin film growth in realtime. The technique generates 3-dimensional heat capacity data as a function of temperature and thickness that show the continuous change during deposition. The measurement interval is ~4×10 nm in thickness, increment of the heat capacity is ~30pJ/K, and the temperature resolution is better than 0.5K.