Semiconductor Nanoparticles Synthesized by Magnetron-Sputtering Inert Gas Condensation: for optoelectronic and phase-change applications

The thesis reports a gas-phase method for synthesizing semiconductor nanoparticles, such as germanium (Ge) and antimony(Sb), with readily size control. Based on the size distribution analysis by transmission electron microscopy (TEM), precise deposition parameters are determined to regulate the size of as-deposited nanoparticles. Because additional chemical agents can be avoided throughout the synthesis process, the as-deposited semiconductor nanoparticles can be considered as the three-dimensional model, allowing us to investigate the novel characteristics of nanoparticles due to the size effect. Specifically, by studying the optical and electrostatic properties of varied size (7 – 14 nm) Ge nanoparticles, the quantum confinement effect for semiconductor nanocrystals has been proven, such that the band gap of Ge nanocrystals can be widen by reducing the size of nanocrystals. Furthermore, due to spatial confinement in three dimensions, the amorphous phase of Sb nanoparticles can be stabilized at room temperature, as demonstrated by electron micrscope