臺灣博碩士論文加值系統

我們將rr-P3HT 及PCBM以不同重量濃度比例混合於化學溶劑，並使用溶劑退火方式塗佈形成電晶體之雙極性薄膜有機半導體層。觀察到當兩種材料在主動層中之比例發生變化之同時，雙極性有機電晶體電性將同步展現電子及電動遷移率之消長變化。此外，在實驗上進一步驗證各種接觸金屬與增添超薄金屬氧化層緩衝層對元件表現之比較。本論文另一重點為發現研製之光電晶體在光照環境下將展現不同之電性調變。最後，由於本實驗之半導體層乃P型及N型之混合層，實驗結果上發現較單一P型或N型半導體有較高之臨界電壓，是以固定P3HT並改以PTCDI-C8置換PCBM作上下雙層結構，明顯的發現利用雙層結構能提升P型電子遷移率及顯著降低操作臨界電壓同時也獲得較佳之N型特性。本研究乃詳盡地研究出以P3HT及PCBM之雙極性電晶體特性並製作出基本反向邏輯電路，發現其光調變特性並對其光調變成因進行探討。半導體材料物性則以原子力顯微鏡、X光繞射儀、X光光電子光譜儀及吸收光譜儀作輔助分析。

Various organic-semiconductor-based ambipolar transistors operated both in positive and negative gate voltage are recently key components in the field of organic complementary-like circuit development. Besides, it will be more potential by adopting solution-processed method or inject-printing methods. In the thesis, two famous organic conducting materials rr-P3HT and PCBM were introduced in developing photosensitive ambipolar field-effect transistors. Herein, we successfully make inverter circuit and let the characteristics discussed in this article. Besides, the variation of hole and electron mobilities are observed and got statistics according to different composite films of P3HT / PCBM ratio. Furthermore, we experimentally introduce different metal electrodes and ultra thin metal oxide layer for comparison to study the performances . In the thesis, another investigation is to fabricate phototransistor with variable characteristics under illumination and these characteristics may be the basis for developing phototransistor and the design of sensor circuit. To decrease the higher threshold voltage both in p-channel and n-channel, bi-layer structure and PTCDI-C8 were introduced to arrive the aim. After studying the characteristics of phototransistor based on the different composite films, we try to explain the mechanism of photoconductivity and photovoltaic effect under illumination. Finally, the semiconductor materials are analysed by AFM, XRD, XPS and UV-visible.

Contents
中文摘要 i
Abstract ii
誌謝 iii
Contents iv
List of Tables vi
Figure Captions vii

Chapter 1 Introduction 1
1.1 Overview Organic Electronics 1
1.2 Overview Organic Ambipoalr Field-effect Transistors 3
1.3 Basic information about P3HT 4
1.4 Basic information about PCBM 6
1.5 Top Contact Structure of Field-Effect -Transistor 7
1.6 Motivations 7
1.7 Thesis Organization 8

Chapter 2 Mechanism and Operation 9
2.1 The Charge Carrier Transportation in Organic
Semiconductors 9
2.2 Hopping Model 10
2.3 Multiple Trapping and Release ( MTR ) 10
2.4 The Operation of Organic Field Effect Transistor 11
2.5 The Parameters Extraction of Organic Thin Film
Transistors 12
2.6 The Principle for the Operation of Complementary-like
Inverter 14

Chapter 3 Experiment 17
3.1 The Materials 17
3.2 The Device Fabrication 18
3.2.1 Substrates Preparation 18
3.2.2 The Surface treatment of Gate/Active Layer
Interface 19
3.2.3 Spin Coating of P3HT/PCBM as the Active Layer 19
3.2.4 Treat with Solvent Annealing and Thermal Annealing 19
3.2.5 Ultra Thin Metal Oxide MoO3 and V2O5
Deposited 19
3.2.6 Evaporation Metal Electrode Onto Semiconductor Layer
as the Electrode 20
3.3 The Device Measurement 21
3.3.1 I-V Characteristics Measurement 21
3.3.2 Surface Morphology Measurement 22

Chapter 4 Results and Discussion 23
4.1 Device Operated In N-Channel, Ambipolar , P-Channel 23
4.1.1 Output Characteristic of Ambipolar Field-effect
Transistor 23
4.1.2 Transfer Characteristic of Ambipolar Field-effect
Transistor 24
4.1.3 Voltage Transfer Characteristic of Complementary-like
Inverter 25
4.1.4 Dependence of Electron / Hole Mobilities on the
Ratio of the Composite Film 30
4.1.5 Devices With Balanced Threshold Voltage 32
4.2 Device with Different Source-Drain Electrodes 33
4.2.1 Device With Ca, Ag, Al and Au as Electrodes
forComparison 33
4.2.2Ultra-Thin Nano-Scale Transition Metal Oxide Layer 36
4.3 The Photoelectric Effect on the Ambipolar Device 40
4.4 The Morphologic Analysis With Different P3HT and PCBM
Composition 47
4.5 The GIXRD Diagram of the Different Composite Films 50
4.6 Bi-layer Ambipolar Field-Effect Transistor Based on
PTCDI-C8 and P3HT 53

Chapter 5 Conclusions 57

References 59

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