| dc.description.abstract | In recent years, quantum dots have been on the rise in the self-assembling processes. For optoelectronic materials, thermoelectric materials and electronic devices applications, the quantum dots, quantum wells and SiGe buffer layer structures have been developed and studied in various ways. Because of the physical properties, such as electrical conductivity and thermal conductivity of the germanium quantum dots are strongly influenced by morphology, composition, strain condition and growth conditions. The formation mechanism of the germanium quantum dots needs to be further studied.
Therefore, this research investigated high-quality SiGe quantum dots at various temperatures, deposition time and carrying gas by ultrahigh vacuum chemical vapor deposition system. The structure included the conventional SiGe quantum dots, composite Ge/Si/Ge quantum dots and triple Ge/Si/Ge/Si/Ge quantum dots. All these three types of quantum dots were performed further annealing treatment or decreased the silicon insert layer thickness. It showed that highly selective wet etching combined with the atomic force microscopy (AFM), transmission electron microscopy (TEM) and Raman spectrum can be used to obtain useful information, which was pertaining to the composition distribution, surface morphology, atomic arrangement and strain condition of the SiGe quantum dots interdiffusion.
Finally, the results of these controllable quantum dots structures in this research can be further applied to the electronic devices. The outcome of the experiments demonstrated that composite germanium quantum dots would be potentially valuable as a new thermoelectric material.
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