如何兼顧響應時間(Response time) 與響應度(Responsivity) 一直是二維光偵測器的一大課題。實驗中，最初發想是以反應離子蝕刻機在特定參數下，使二硫化鎢的單晶能產生鬆動與缺陷，而後在大氣環境下氧化使之出現細小孔洞，並用二次成長的方式填入二硒化鎢，以此作為元件的通道材料，期望利用typeII二維側向異質結構，在照光後激發出電子電洞，藉由二硒化鎢抓住電洞而吸引電子來達到額外的光增益。但由於反應離子蝕刻參數所造成的缺陷數量容易過多，時常造成元件電性由原本二硫化鎢的N型轉變為二硒化鎢的P 型，故在接下來的一系列實驗，除了嘗試不同參數對於電性量測結果的改變外，也利用以二硫化鎢做為主要通道，並以不同結構堆疊來實現高增益、高響應度(Responsivity)、高探測率(Detectivity)、低響應時間(Response time) 等等光電特性。而在改善金屬電極與二維半導體通道的接觸上也下了功夫，利用石墨烯做為接觸電極的材料，有效解決費米能階釘札(Fermi level pinning) 和蕭特基能障等問題。

It’s always a issue to acheive both response time and responsivity at the same time.For the experiment,the origin idea is using reation ion etching(RIE) process let WS2 crytical loosen and pocess defect,then oxidize in the atmosphere for 10 minutes in order to obtain the quantumsize dot.After that,do the secondgrowth CVD process of WSe2 which can embed the WSe2 quantum dot into the WS2 crystal.Use the product which under go the process of secondgrowth CVD as the channel material.It is expected that through the photogating effect and the photoconductive effect, the typeII lateral heterostructure will have good photo gain performance.But the results turn out to be fail.Due to Coulomb scattering and excessive defects in the WS 2 channel, the excess WSe 2 makes the ntype device ptype. Therefore, the focus of this series of experiments will be on comparing different structures.
Use different stacking sequence to obtain a device with high gain, high responsivity, high detectivity, high on/off ratio and low response time.In addition, the use of graphene electrodes can improve contact problems, such as Fermi level pinning and Schottky barriers.

目錄
Abstract......................................................... III
論文摘要........................................................... V
目錄............................................................ VIII
第一章緒論.......................................................... 1
1.1 半導體技術演進.................................................. 1
1.2 傳統半導體的微縮與極限........................................... 3
1.3 二維材料發展.................................................... 3
1.4 半導體光偵測器介紹.............................................. 5
1.5 論文架構....................................................... 10
第二章材料製備與檢測................................................ 11
2.1 石墨烯與過渡金屬二硫屬化合物介紹................................. 11
2.1.1 石墨烯介紹................................................... 11
2.1.2 過渡金屬二硫化合物介紹........................................ 17
2.2 石墨烯與過渡金屬二硫屬化合物製備................................. 21
2.2.1 機械剝離法(Machanical exfoliaion)............................ 21
2.2.2 化學氣相沉積法(Chemical vapor deposition).................... 22
2.3 石墨烯與過渡金屬二硫屬化合物檢測................................. 23
2.3.1 拉曼散射頻譜................................................. 23
2.3.2 光致螢光光譜................................................. 28
第三章結構設計..................................................... 31
3.1 石墨烯接觸電極................................................. 31
3.2 QD/WS2元件.................................................... 32
3.3 QD/WS2元件堆疊WS2.............................................. 33
3.4 Gr/WS2/nWSe2.................................................. 34
第四章元件製程..................................................... 35
4.1 二維材料之製備與檢測............................................ 35
4.1.1 石墨烯...................................................... 35
4.1.2 二硫化鎢..................................................... 37
4.1.3 二硒化鎢..................................................... 40
4.2 QD/WS2製程.................................................... 44
4.3 石墨烯接觸電極................................................. 48
4.4 材料堆疊轉移................................................... 50
第五章光電子電晶體特性量測與分析..................................... 53
5.1 基本電晶體量測與分析............................................ 53
5.1.1 元件量測方法與量測系統........................................ 53
5.1.2 量測結果與分析............................................... 54
5.2 能帶與能障分析................................................. 62
5.3 光電特性量測與分析............................................. 64
5.3.1 光電特性量測系統............................................. 64
5.3.2 光響應度..................................................... 65
5.3.3 探測率...................................................... 71
5.3.4 響應時間與照光電流開關比...................................... 72
第六章結論與未來展望................................................ 77
參考文獻........................................................... 79

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