單電子偵測器原理及製作與二維電子氣量子點電荷傳輸行為

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/69262

Title:	單電子偵測器原理及製作與二維電子氣量子點電荷傳輸行為
Authors:	廖俊霖;Liao,Chun-Lin
Contributors:	物理學系
Keywords:	單電子偵測器;二維電子氣;single-electron device;2DEG
Date:	2015-11-27
Issue Date:	2016-01-05 17:47:19 (UTC+8)
Publisher:	國立中央大學
Abstract:	在本論文中我們研究兩種奈米尺度的元件，分別為單電子元件(single-electron devices)以及量子尖端結構(QPC)之二維電子氣元件，本實驗的單電子元件是由單電子電晶體(single-electron transistor)與單電子箱(single-electron box)組成，二維電子氣元件則由國立清華大學陳正中教授實驗團隊所提供。單電子電晶體的中央金屬島與兩側電極透過穿隧能障接合，利用其奈米尺度的結構使得充電能量大幅上升，並造就較明顯之庫倫阻絕效應，量測時我們將元件放置於氦稀釋冷凍機內，使系統中電荷數目不受熱擾動影響而發生變化。單電子電晶體的電流受環境靜電能影響而變化，可做為單電子偵測器，因此我們將單電子電晶體與單電子箱以電容相連接，並透過電子電晶體的電流變化來偵測單電子箱的電荷傳輸事件。本論文製作兩種不同全鋁/鋁鈀的單電子電晶體，並分析探討、製作流程、以及製作參數，最後完成單電子電晶體元件二維電子氣元件為異質階面結構GaAs/AlGaAs，我們在元件中成功侷限出窄通道，觀測到量子化電導率，並利用QPC導電行為易受環境電位影響的特性作為單電子偵測器，觀測在二維電子氣侷限出之量子點內單電子電荷傳輸行為。最後在本實驗研究上，我們成功以單電子電晶體與量子尖端結構(QPC)作為單電子偵測器，並觀測到單一電荷傳輸事件。 ;In this thesis, we study two types of nanoscale electronic devices, single-electron devices and quantum point contact (QPC) formed in two-dimensional electron gas (2DEG). The system of single-electron devices we study is composed of a single-electron transistor (SET) and a single-electron box (SEB). The 2DEG devices are provided by Professor Jeng-Chung Chen research group in the National Tsing Hua University. In a SET, a central island connects to source and drain electrodes through two tunnel barriers. As the structure is made in nanoscale, charging energy is large, and Coulomb blockade effect should be pronounced. To perform the experiments, we placed the devices in a helium dilution refrigerator to reduce the thermal fluctuation effect. The current of SETs will be affected by surrounding electric potential. Therefore, by capacitively coupling a SET to a SEB, we can detect the charge tunneling events in the SEB by reading the current in the SET. In the thesis, we study all-aluminian and aluminian-palladium SETs, analyze fabrication process, parameter, and finally fabricate workable Single-Electron Devices. The 2DEG we study is formed in heterojunction between GaAs and AlGaAs, we succeed to form QPC and observe quantized conductance. The conductance of QPC is affected by surrounding electric potential and we utilize as a Charge sensor to observe the charge transport behavior in quantum dots . In this study, we successfully observe single electron tunneling events in both Single-Electron boxes and 2DEGs quantum dot by utilizing SETs and QPC , respectively , as charge sensors.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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