Abstract
Atomic diffusion is a fundamental process that dictates material science and engineering. Direct visualization of atomic diffusion process in in situ ultrahigh vacuum TEM could comprehend the fundamental information about interface dynamics, phase transitions, and different nanostructure growth/migration phenomenon. This thesis is comprised of the in situ TEM observations of the electronmigration and electrical properties of nanocrystal-modified Ag NWs, the formation of In2O3 hollow nanoparticles/ZnO heterostructure, and the complete replacement of ZnO nanowires by indium. In situ TEM analyses reveal that electromigration in the twinned Ag NW could be inhibited at the boundaries of twin and stacking fault in the first study. The rate and activation energy of indium atoms diffusing into ZnO nanowires are measured in the second study. The third study demonstrates the replacement processes strongly depend and dominated by the interface dynamics between indium and ZnO. The processes are explained based on thermodynamic evaluation and growth kinetics. These results present the potential possibilities to increase the lifetime of nanodevices by the nanocrystal-modified Ag NWs, and to completely replace metal-oxide semiconductor with metal nanowire without oxidation and form crystalline metal nanowire with precise epitaxial metal-semiconductor atomic interface. Formation of such single crystalline metal nanowire without oxidation by diffusion to the metal oxide is unique and it is crucial in nanodevice performances, rather challenging in manufacturing perspective in 1D nanodevices.