自組裝鍺量子點在近年來已引起廣泛之興趣，矽鍺之量子點，量子井及矽鍺緩衝層的成長已在多處被開發及研究，其中在光電材料、熱電材料與電子元件，亦有許多的應用。本研究更進一步探討複合式鍺量子點之形成機制，因為對複合式鍺量子點之導電、導熱以及熱電優值等物理特性，與其形貌結構、應力狀態、成份分佈、生長條件有著密不可分的關係。總結上述之分析，本研究探討以超高真空化學氣相沉積系統所製備出之不同溫度、沉積時間及氣流之高品質矽鍺量子點，其結構包含傳統式矽鍺量子點、複合式鍺卅矽卅鍺量子點及三重複合式鍺卅矽卅鍺卅矽卅鍺量子點，並將量子點經退火處理及改變其中矽嵌入層之厚度。以高選擇性濕式化學蝕刻溶液搭配原子力顯微鏡、穿透式電子顯微鏡和拉曼光譜儀針對矽鍺量子點之內部矽鍺相互擴散之成份分佈、表面形態、原子排列以及應力狀態深入之分析，進而控制量子點將此研究結果應用至元件上，經由量測可以得知複合式鍺量子點在熱電元件的製作是具有未來發展的可能性。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.
