半導體製程技術不斷突破，挑戰元件尺寸微縮的極限；而先進的量子點成長技 術，更使得研究人員在室溫下就能觀察到單電子電晶體的主要元件特性－庫論阻斷效 應。 本文利用非平衡態的格林函數，系統化探討一系列單電子電晶體之穿隧電流頻譜 表現，以利於實驗量測上定性判別譜線成因和解釋現象；其中在單一能階系統中，格 林函數已能反應出電子內階庫倫交互作用，引起電流呈現庫倫階梯及庫倫震盪形式； 在二能階以上的系統，格林函數亦能涵蓋外階庫倫交互作用，描述更複雜的穿隧電流 頻譜；在非對稱穿隧率的系統當中，「殼層穿隧」與「殼層填充」兩種不同的限制條 件下，在頻譜上會選擇性增強或消除量子點裸能階之共振通道訊息；溫度影響電極電 子之費米分佈，使高溫下載子填充較為緩和；此外，將金屬電極更換成重參雜之半導 體電極，由於半導體電極本身載子有效帶寬比電極薄，當有一側電極之能隙對齊到已 開啟之共振通道，則該通道之電流將會立即被關閉。 The main purpose of this dissertation is to theoretically study the transport properties of single-electron transistors (SETs) based on the formalism derived by authors David M. T. Kuo and Y. C. Chang [arXiv:con-mat/0702095v1 (2007)]. The Coulomb staircase and Coulomb oscillation of tunneling current can be easily clarified in a nanostructure junction of one-level system. We also study the tunneling current of SETs in the shell-tunneling and shell-filling cases. Apart from that, temperature effect on the tunneling current through multi energy levels is investigated. We found that the tunneling current feature of Coulomb staircase and Coulomb oscillation with respect to the source-drain voltage difference can be simultaneously observed in a nanojunction system with semiconductor electrodes due to asymmetrical carrier density available in the S/D electrodes.
