本論文是首篇，實現了以單層石墨烯作為電晶體基極的研究，且針對此異質接面電晶體的基本電性和照光後行為，做更深入的探討。由於石墨烯許多獨特的特性，像是高載子遷移率、二維狀態下可穩定存在還有可大規模的生產，讓他有潛力應用在高速的電子元件當中，近年來吸引了許多人投入石墨烯的研究。本篇論文希望能將石墨烯薄膜應用於電晶體(transistor)的基極端，單層至數層的石墨烯薄膜可以形成非常薄的基極厚度，我們預期會有較低的載子複合率，期望製作出一個具有高共射極電流增益(common-emitter current gain)的元件。且較薄的基極厚度，可降低基極端的串聯電阻，提升元件的操縱速度。目前已經有些相關的論文對這樣的架構進行模擬，並得到一些不錯的結果，但尚未有人將它實現。本篇論文致力於將此概念的電晶體實現，且對原先提出的架構加以修正以符合我們能夠取得的製程方式。
經由Gummel Plot量測，我們得到此電晶體最大的共射極電流增益(common-emitter current gain)可以達到104左右，量測到的共基極電流增益(common-base current gain)可以非常的接近1，而透過理論推導整理的基極區傳輸因數(base transport factor)也可以達到0.9左右，和目前現有的石墨烯熱載子電晶體(graphene base hot electron transisitor)相比可以說有非常大的進步[ 10 ]。另一方面，我們會探討將此石墨烯電晶體作為光偵測電晶體的表現。在波長520nm，照光功率為1.25uW的情況下，此電晶體的電流響應度最高可以達到2.24A/W，電壓響應度最高可以達到1.36x105V/W。現有的石墨烯二極體，電流響應度在波長488nm，照光功率為1.23uW的情況下為0.225A/W，電壓響應度則是大約為4x104V/W[ 19 ]。以照光後的響應度來看，本論文所完成的石墨烯電晶體，和石墨烯二極體相比，整體的表現都有不錯的提升。

This thesis is the first research which implements the concept of using single layer graphene as base terminal of a transistor and discusses the electrical and optical properties of this novel device. Graphene has attracted lots of interests due to its unique properties such as high mobility, 2-D structure and large scale production. These characteristics make it attractive for high-speed electronic devices. Our study here is planning to utilize graphene film as the base material in a transistor. Due to the thin graphene layer (single layer to few layers), we expect it to have very little recombination in the base, which can contribute a large current gain and also minimize the series resistance to enable high speed operations. There were some papers studying the simulation of this kind of devices, but no one has implemented it yet. In this thesis, the graphene base transistor is realized for the first time, and we focus on designing the structure and optimizing the process flow of manufacturing.
Through the measurement of Gummel plot, we find the common-emitter current gain of this transistor can achieve 104, and the common-base current gain reaches very close to 1. Furthermore, by theoretical calculation, its base transport factor can be close to 0.9. Compared with the result of graphene base hot electron transistor, our work shows very significant improvement [ 10 ]. In the meantime, we study the transistor’s potential as a phototransistor (PT). The current responsivity of this device can reach 2.24A/W, and the voltage responsivity can attain 1.36x105V/W under the exposure of green light LED (λ=520nm, P=1.25uW). Compared with the performance of graphene/silicon photodiode [ 19 ], whose current responsivity is 0.225A/W and voltage responsivity is 4x104V/W (λ=488nm, P=1.23uW), the graphene base transistor of this thesis has better performance in both current responsivity and voltage responsivity.

摘要 I
Abstract II
致謝 IV
目錄 VI
圖目錄 VIII
表目錄 XIII
第一章 前言 2
1.1 石墨烯材料的發展及應用 2
1.2 研究動機 3
1.3 論文章節架構 7
第二章 石墨烯的基礎特性 8
2.1 石墨烯的物理特性 8
2.2 拉曼光譜分析 11
2.2.1 拉曼散色的基本原理 11
2.2.2 石墨烯的拉曼光分析 11
第三章 光偵測器原理及特性簡介 14
3.1 光二極體原理 14
3.2 雙極光電晶體原理 15
3.3 蕭特基與歐姆接面 17
3.4 光偵測器的特性簡介 20
3.4.1 暗電流(Dark current)&雜訊(Noise) 20
3.4.2 量子效率(Quantum efficiency) 20
3.4.3 響應度(Responsivity) 22
3.4.4 響應速度(Response time) 23
第四章 石墨烯光偵測器實作 24
4.1 元件設計與架構 24
4.1.1 異質接面雙極性電晶體介紹 24
4.1.2 雙極性電晶體特性推導 25
4.1.3 元件架構 28
4.2 石墨烯的成長與轉移 34
4.2.1 高溫金屬催化成長石墨烯 34
4.2.2 銅箔的預處理及石墨烯的成長參數與結果 36
4.2.3 石墨烯的轉移(transfer) 40
4.3 元件製作與製程 48
4.3.1 破片樣品製作 48
4.3.2 正片樣品製作 51
第五章 量測結果與討論 63
5.1 量測儀器簡介 63
5.2 量測方式 64
5.2.1 電流對電壓量測 64
5.2.2 Gummel Plot 65
5.2.3 電壓響應度 65
5.2.4 光點大小量測 66
5.3 量測結果 67
5.3.1 電性量測 67
5.3.2 照光量測 77
第六章 結論與未來展望 87
6.1 結論 87
6.2 未來展望 89
參考文獻 90

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